The ASTRANIT Center is based on mutual synergy. On one hand, the project will help the LABONIT project to streamline the technological preparation of nitride hetero-structures thanks to the rapid response from the structure analysis, which will provide vital information about the quality and structure of the samples. This necessary feedback would not be possible without the ASTRA laboratory. On the other hand, the advanced structure analysis laboratory ASTRA will be able to expand its focus on structure analysis of thin films and cooperation with industry in this area.

Project of the Czech Science Foundation Nitride heterostructures for fast detection of ionizing radiation (2016 - 2018)

In the frame of the project, nitride heterostructure containing multiple quantum wells which can work as fast scintillation detector of ionizing radiation will be developed and prepared. To decrease the luminescence decay time and increase the luminescence intensity, it is necessary to increase the overlap of electron-hole wave functions in quantum wells (QWs) which are spatially separated by polarization on heterostructure interfaces. Three possible ways of increasing the wave function overlap will be tested in this project: thinning of QW thickness, introduction of deep InGaN QW into the shallow QW and polarization balancing of QW and barrier layers by proper composition of AlInGaN. Strain compensation will allow us to prepare sufficiently thick active region necessary to capture dominat part of incident radiation.

Postdoctoral project of the Czech Science Foundation
Intermediate band solar cells

(2014 - 2016)

Intermediate band solar cell theoretically offer a promising way to significantly increase cell efficiency compared to a single-junction solar cell. In the frame of this project I would like to prepare intermediate solar cell devices by MOVPE technology on GaAs substrates. Intermediate band will be created by several types of quantum dot structures with emphasis on structures with type-II band alignment. Type-II QD properties such as the charge separation and related long radiative life time improves charge extraction in these structures and makes them very suitable for solar cell applications. To increase light absorption I propose new type II vertically aligned QD structures combing in one stack QDs from different materials. The structural properties of the solar cells will be tuned to increase its efficiency. The main goal of this project is enhancement of solar cell efficiency in semiconductor structures with intermediate band formed by multiple stacks of vertically correlated QDs or combined QDs dominantly with type-II band alignment for enhanced electron and hole separation.

Project of the EC
TERA-MIR Radiation: Materials, Generation, Detection and Applications
MPNS COST Action MP1204
(2013 - 2016)

The main objective of this action is to advance novel materials, concepts and device designs for generating and detecting THz (0.3 THz to 10 THz) and Mid Infrared (10 THz to 100 THz) radiation using semiconductor, superconductor, metamaterials and lasers and to beneficially exploit their common aspects within a synergetic approach. We shall use the unique networking and capacity-building capabilities provided by the COST framework to unify these two spectral domains from their common aspects of sources, detectors, materials and applications. The key instruments of the action will be meetings of the working groups, Round Robin actions, Short Term Scientific missions (STSMs) and annual Workshops.  We will create a platform to investigate interdisciplinary topics in Physics, Electrical Engineering and Technology, Applied Chemistry, Materials Sciences and Biology and Radio Astronomy. In this common sense THz and MIR are considered jointly, the driving force for both regimes being applications. The main emphasis will be on new fundamental material properties, concepts and device designs that are likely to open the way to new products or to the exploitation of new technologies in the fields of sensing, healthcare, biology, and industrial applications. End users are: research centres, academic, well-established and start-up Companies and hospitals

Project of the Czech Science Foundation
GaSb based nano-heterostructures with deep quantum well
13-15286S
(2013 - 2015)

Heterostructures with deep Al(As)Sb/InAsSb/Al(As)Sb quantum well with GaSb barriers will be prepared and studied by photoluminescence and electroluminescence. Demonstration of the effect of superlinear dependence of the luminescence intensity and an enhancement of optical power will be performed on this heterostructure with single quantum well and afterwards with multiple quantum wells. The results of the measurements will lead to the proposal of a new type of mid-infrared lasers with low threshold current.

Nahoru

Project of MSMT
III-V semiconductor heterostructures/nanostructures towards innovative electronic and photonic applications
MSMT 7AMB12GR034 
(2012 - 2013)

The project aims at the atomic scale profound understanding and tailoring of growth mechanisms, microstructure and physical properties of highly mismatched III-V heterostructures, quantum dot (QD) nanostructures and metal nanoparticles (MNPs) grown on nanoporous and compact substrates. Periodic porous structures in InP and GaAs will be prepared by electrochemical etching and In_xGa_1-xAs_yP_1-y layers and InAs/GaAs QDs will be grown by liquid and metal organic vapour phase epitaxy. Schottky barriers will be formed by MNPs deposition onto InP by electrophoresis and by photoinduced decomposition of inorganic salts. Quantitative transmission electron microscopy will be used to study the nucleation mechanisms the microstructure of the epilayers, the shape and size of QDs and MNPs the local interfacial structure and the strain distribution at the heterointerfaces. Physical properties will be characterized by ballistic electron emission spectroscopy, photoluminescence and microcathodoluminescence.

Nahoru

Project of the Czech Science Foundation
Lattice mismatch compensation in heteroepitaxy on micro and nanoporous A³B⁵ semiconductors
and deposition of metals and semiconductors into micropores
P108/10/0253
(2010 - 2012)

This project focuses on the epitaxial growth of highly mismatched heterostructures on porous substrates of A3B5 semiconductors and on the deposition of metallic and semiconductor materials into micropores. Preparation of high quality lattice mismatched epitaxial layers is one of the most challenging tasks in semiconductor technology. Electrochemically prepared micro and nanopores in InP and GaAs will be overgrown by LPE and MOCVD to evaluate (i) the conversion of pores into microbubbles and microlamellae, (ii) the expected reduction of dislocation density in the overgown layer, (iii) the strain distribution at heterointerfaces. Remote plasma CVD and electrochemical deposition will be used to deposit ZnO into micropores and onto porous GaP substrates to study the unique optical properties of these structures. Pt will be deposited electrochemically into porous networks as the first step towards the preparation of metamaterials. Structural, electrical, and optical properties will be investigated by optical microscopy, SEM, AFM, SIMS, wet etching, Hall measurement, PL, and microCL.

Nahoru

Project of the Czech Science Foundation
Quantum dots for detectors and other devices
P102/10/1201
(2010 - 2012)

Project of the Czech Science Foundation
Measurement of vapour pressure of metal organic and related precursors for use in nanostructure production
203/08/0217
(2008 - 2010)

in cooperation with: Institue of Chemical Technology, Prague, Dep. of Physical Chemistry

Knowledge of accurate data on vapour pressure of metal organic precursors such as carboniles, acetylacetonates or metalocenes is essential for control and modelling of growth of semiconductor and metallic layers, nanostructures and nanoparticles. These structures are indispensable in optoelectronics and high speed electronics, in preparation of new semiconductor, dielectric, magnetic and ceramic materials, in catalysis and related chemical processes. Data on vapour pressure of metal organic precursors presented in literature often exhibit a great scatter or are unknown. Static apparatuses for vapour pressure measurement developed at ICT Prague and at IP AS CR (the latter for toxic and dangerous materials) are suitable for highly reactive precursors having low vapour pressure. The project is aimed at measuring and critically assessing vapour pressure data of metal organic and related precursors containing Ni, Fe, Mn, In, Sb and Li used in MOVPE and CVD.

Nahoru

 Grant Agency of the Academy of Sciences of the Czech Republic Project
  Controlled preparation of semiconductor Quantum Dots
GAAV IAA100100719
(2007 - 2009)

This project aims at the development of semiconductor Quantum Dots (QDs) with predetermined and controlled size and shape from InAs and later from GaSb, using MOVPE. Optical and electrical properties of QD structures are often determined more by the size and shape, than by the material of the QDs, because of the comparable size of QDs and de Broglie´s wavelength for electrons and holes. The type of the structure, (number of QD layers and their separation in the vertically correlated structures) will play important role in the optimisation of QD structure parameters. The above mentioned properties are determined by the technology of preparation. The QD parameters will be adjusted by changing the growth rate, precursor ratio, time regime of the growth and by other technological parameters like the substrate orientation. The dominant technology for QD preparation structures is MBE. In the frame of this project we would like to prove that MOVPE is equally suitable method for this task.

Nahoru

European Community Project

New mid-infrared sources for photonic sensors (NEMIS)
031845
(2006 - 2009)

in cooperation with:
Technical University Munich, Germany
University of Montpellier 2, France
Chalmers Technical University, Gőteborg, Sweden
VERTILAS, GmbH, Germany
Omnisens SA, Switzerland
Siemens AG, Germany

The NEMIS project aims at the development and realisation of compact and packaged vertical-cavity surface-emitting semiconductor laser diodes (VCSEL) for the 2-3.5µm wavelength range and to demonstrate a pilot photonic sensing system for trace gas analysis using these new sources. The availability of electrically pumped VCSELs with their low-cost potential in this wavelength range that operate continuously at or at least near roomtemperature and emit in a single transverse and longitudinal mode (i. e. single-frequency lasers) is considered a basic breakthrough for laser-based optical sensing applications. These devices are also mode-hop-free tuneable over a couple of nanometers via the laser current or the heatsink temperature. They are therefore ideal and unmatched sources for the spectroscopic analysis of gases and the detection of many environmentally important and/or toxic trace-gases, which is a market in the order of 10 million Euro today with an expected increase into several 100 million Euro with the availability of the new VCSELs.
The semiconductor technology underlying the VCSELs relies on GaSb-based quantum well structures and the devices are based on insulating apertures as well as on buried tunnel junctions for the lateral current and mode confinement. The project is organized into six workpackages dedicated to specifications/design, epitaxy, VCSEL technology, VCSEL characterisation, applications, and project management. The consortium comprises seven complementary and highly skilled partners from five European countries: Technische Universität München, Germany (buried-tunnel-junction VCSEL), Universite Montpellier 2, France (insulator-confined VCSEL), Institute of Physics of the Academy of Sciences, Czech Republic (VCSEL characterisation), Chalmers University of Technology, Sweden (Design), VERTILAS GmbH, Germany (VCSEL packaging and characterisation), Omnisens, Switzerland (Applications) and Siemens AG, Germany (Applications).

Nahoru

Grant Agency of the Academy of Sciences of the Czech Republic Project
Morfology of Quantum Dots and its impact to the electronic structure
GAAV B101630601
(2006 - 2007)

in cooperation with: Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

The aim of the project is to optimize the morphology of QD for application in active layer of QD lasers. The proper luminescence energy (wavelength of 1.3 micrometers and 1.55 micrometers), sufficient distance of the ground and excited transitions, and good homogeneity have a great importance for the optoelectronic applications of quantum dots (QD). All these properties can be controlled by the technology of the capping layer above the QD. We will examine an impact of the growth rate of the capping layer, its composition (InGaAs, AlGaAs), and partial pressure of the arsin on the properties of produced dots. Prepared structures will be investigated by PL, MPL, TEM, and AFM. Using the proper model of quantum dots (based on the approximative separation of the coordinates and including the effects of the strain), the dots shape and size, homogeneity of the dots ensembles, and effective masses of the electrons and holes will be determined.

Nahoru

Project of the Czech Science Foundation
Quantum dot engineering
202/06/0718
(2006 - 2008)

Project of the Group of Optical Measurements and Transport Theory, our Dep. of Semiconductors, Institute of Physics, AS CR

Preparation of high brightness luminescent vertically stacked multiple-layer InAs quantum dots (QD) structures with defined properties; the emission wavelength, the energy difference between the QD first excited and ground states and the density of QDs. Stacked multi-layer QD structures will be prepared by Metal Organic Vapour Phase Epitaxy, using Stransky-Krastanov growth mechanism. Parameters like the number of stacked layers, the thickness of GaAs spacer layers, thickness and chemical composition of strained buffer layer will be used to control properties of vertically stacked multiple-layer InAs QDs structures. Optimised structure will be incorporated into GaAlAs/GaAs waveguide. Samples will be characterized by structural methods (X-ray diffraction, transmission electron microscopy (TEM), and atomic force microscopy (AFM)) and optical methods (luminescence, magneto-luminescence, absorption, photomodulated reflectance, elipsometry and photoconductivity). Electronic structure of QDs will be calculated and the results of calculation will be used to modelling of optical properties of prepared structures. The aim of these studies is to contribute to control preparation of stacked multiple-layer structures of quantum dots and to understand their properties in dependence on the value main parameters of these structures.

Nahoru

Project of the Czech Science Foundation
Space resolved ballistic electron emission spectroscopy on individualInAs/GaAs quantum dots embedded in AlGaAs barriers
202/05/0242
(2005 - 2007)

in cooperation with:
Institute of Radio Engineering and Electronics Academy of Sciences of the Czech Republic
Institute of Information Theory and Automation Academy of Sciences of the Czech Republic

The InAs quantum dots (QDs) in GaAs embedded in AlGaAs barriers will be studied by ballistic electron emission microscope BEEM). The detailed space resolved ballistic electron emission spectroscopy (BEES) on these QDs will be the main aim of the project. The density of states and the transmissivity of individual quantum states will be mapped in QD. The special software will be developed for realization of such measurements. The samples will be prepared by MOVPE (Metal Organic Vapor Phase Epitaxy) technique and results of measurements will be compared with results measured on MBE (Molecular Beem Epitaxy) grown samples (University of Nottingham). The results contribute to increasing knowledge about QDs which are necessary for development of high efficient lasers, ultrasmall memories and single photon sources.

Nahoru

EC Network of Excellence NoE
Photonic Integrated Components and Circuits - ePIX
(2004 - 2009)

New materials, such as quantum-dot materials and self-organised semiconductors, are of key importance in a variety of components with high performance. The demanding technologies needed for research on those materials are the focus of this theme. As in the network theme Towards technologies for photonic large scale integration and Nanophotonics for advanced integration schemes the complexity and cost of those technologies are the key motivation for integration of research.

Nahoru

Project of the Czech Science Foundation
Accurate measurement of vapour pressure of organometalics
203/04/0484
(2004 - 2006)

in cooperation with: Institute of Chemical Technology, Prague, Dep. of Physical Chemistry

The precise knowledge of precise vapour pressure data of metal organic precursors is indispensable for MOVPE process optimisation - now the main epitaxial technology for optoelectronic and ultrafast electronic components. The wide scatter of the published data has not been systematically and critically assessed yet, to give the user up to date and reliable data. Because of the pyrophoric nature of metal organic precursors the most suitable measuring technique for vapour pressure is the static method. The third generation of the vapour pressure static apparatus designed at ICT Prague has a minimised electro polished internal surface, ultrahigh vacuum design with two turbomolecular pumps, precise temperature control and uses a differential pressure gauge MKS Baratron. We have recently published the true vapour pressure data of high purity DEZ, TESb, TEAl, TEGa. The measurement was carried out in the temperature range used for MOVPE. The objective of the project is to measure, critically assess and eventually update the vapour pressure data for other old and new metal organic precursors used for MOVPE.

Nahoru

Grant Agency of the Academy of Sciences of the Czech Republic Project
Radiative recombination mechanism of subnanometric InAs/GaAs laser structures
A 1010318 GAAV
(2003 - 2005)

in cooperation with: Faculty of Electrical Engeneering (Dep. of Microelectronics), Czech Technical University, Prague

To explain the discrepancy between the experimental results and theoretical models of the shift of emission energies of luminescence and absorption edge of laser structures with changing configuration of ultrathin InAs layers in the active region.
The proposers have been preparing and studying semiconductor laser structures with one or more thin InAs layers (several monoatomic layer thick) and only several nanometers apart for several years already. The shift of the position of the El, PL maxima and that of the absorption edge depend on the thickness, number and separation of these InAs layers and has been found to be in the range of hundreds of meV. The present theories predict shifts in the range of tens of meV. New laser structures will be proposed and prepared by MOVPE and studied by EL, PL, and in plane photoconduction spectroscopy. These results will be used for verification of the theoretical models for simulation of the radiative recombination process. The aim of the project is to propose a model, capable of explaining the experimentally measured shifts of the emission and absorption energies with the change of configuration of the layer structure and use these results for the process of optimisation of laser performance.

Nahoru

Project of the Czech Science Foundation
Quantum dots with long wavelength emission
202/03/0413
(2003 - 2005)

Project of the Group of Optical Measurements and Transport Theory, our Dep. of Semiconductors, Inst. of Physics, AS CR

in cooperation with: Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

Preparation of single- and multiple-layer structures of quantum dots (QD) with emission wavelength above 1.3 microns. QDs will be prepared by MOVPE, using Stransky-Krastanov growth mechanism. QD structures will be grown using InGaAs system. The emission wavelength will be adjusted by changing the composition of QDs and barriers, which controls the lattice constants and gap. Samples will be characterised by X-ray diffraction, optical methods and microscope techniques. The aim of these studies is to  contribute to understanding of the electronic structure in QDs in dependence on the composition of QDs and barriers.

Nahoru

Project of the Czech Science Foundation
Quantum size strained semiconductor structures prepared by MOVPE technology
202/02/D069
(2002 - 2005)

Structures with high values of misfit (5-7%) and strain may result in two possible epitaxial structures according to technological parameters: quantum dots (QD) and isovalent delta-layers (IDL) - i.e. ultrathin quantum wells with thickness of only few atomic layers. The use of these structures in laser active region may lead to much better parameters compared with conventional quantum wells lasers (lower threshold current density, better temperature stability of threshold current, higher differential efficiency, higher power and lower losses). The main part of the work will be devoted to the design and MOVPE preparation of QD and IDL structures based on InAs/GaAs and InSb/GaSb, optimisation of technological parameters of preparation and increasing localization energy in QDs. Structures suitable for laser active regions in desired wavelength ranges (1300nm - the window in fibre waveguides, midinfrared region) and AlGaAs waveguide prepared without destroying the QD luminescence be the main goal. The aim will be to solve quantitatively some questions, which are at present subjects of intense discussion as energy spectra of the conducting and valence band in IDL or mutual influence of IDLs causing red shift of photoluminescence peaks. It is impossible to explain this red shift only by overlapping of electron wavefunctions. Polarization measurements should evidence the dimensionality of our structures and bring some information about the strain inside QDs.

Nahoru

Information Society Technologies (IST) Programme

GLADIS - Gas Laser Analysis by Infra-red Spectroscopy
IST-2001-35178
(2002 - 2005)

in cooperation with:
Actaris SAS, Germany
Schlumberger Industries SA, France
University of Montpellier 2, France
Thales, France
Nanoplus, Germany
Gaz de France, France
Gas Natural, Spain
Omnisens, Switzerland

The objective of the project is to develop a microsystem for infra red spectroscopy, that will be integrated in a cost effective optical device for the measurement of natural gas calorific power. This device targets the gas distribution network, where the quantities are large. The measurement will be based on gas composition analysis by infrared spectroscopy. The laser technology has been retained to achieve this component. Three different types of lasers will be studied within the project. The objectives of the project are to select one laser solution and to achieve the integration of the retained solution.Three European end users will test and validate the whole optical device.

Nahoru

European Community Networks in Nanotechnology
http://www.cordis.lu/nanotechnology/src/networks.html

MOVPE prepared materials and structures for electronics and optoelectronic devices
Index: 52
(2001 - )

Czech participating organisations:

Charles University, Prague, Faculty of Mathematics and Physics, Dep. of Macromolecular Physics
Institute of Chemical Technology, Prague, Dep. of Solid State Engineering
Czech Technical University, Prague, Faculty of Electrical Engineering, Dep. of Microelectronic
Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

Development of the Metal-Organic Vapour Phase Epitaxy technology (MOVPE) of thin & ultrathin layer for deposition of III-V semiconductors.  Co-operating laboratories both inside/outside the Institute have mastered a wide range of characterisation techniques and have started their own programmes based on MOVPE generated structures. Concentrate our efforts: Quantum Dots, Wells. Optical waveguides, Ohmic contact. Active waveguide structures, Opitcal sensor structures, Diodes and transistors based on quantum effects. Defects in multiple QDs, strained superlattices (SL). Focus our expected publication efforts on fundamental aspects of quantum dimensional objects (QW, QD) and on behaviour of different types of A^III-B^V heterointerfaces.

Nahoru

  Project of the Czech Science Foundation

MOVPE prepared materials and structures for electronic and optoelectronic devices
(1999 - 2001) 
102/98/0414

in cooperation with:

Charles University, Prague, Faculty of Mathematics and Physics, Dep. of Semiconductor Physics
Institute of Chemical Technology, Prague, Dep. of Solid State Engineering
Czech Technical University, Prague, Faculty of Electrical Engineering, Dep. of Microelectronic
Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

During the period of the last six years Institute of Physics AV-CR has gradually developed the MOVPE (Metal-Organic Vapour Phase Epitaxy) technology of thin and ultrathin layer deposition of III-V semiconductors. Co-operating laboratories both inside as well as outside the Institute have mastered a wide range of characterisation techniques and have started their own programmes based on MOVPE generated structures. In the coming three year period of continuing co-operation of Academic and University research groups (MFF-Charles Univ., UIPL-Chem. Univ., FEL-Czech Tech. Univ., PrF-Masaryk Univ.) we would like to extend the use of our technological and characterisation expertise for the preparation of device type semiconductor structures or structures otherwise related to solving application problems. We would like to concentrate our efforts in the following fields: Quantum Dots - (QD), Quantum Wells - (QW) including strained structures for semiconductor lasers or detectors, Hall sensors - (FzU). Photovoltaic structures with QWs (MFF). Optical waveguides and ohmic contacts (VŠCHT). Active waveguide structures, Sensor structures, Resonance tunnelling (FEL). Multiple QD structures and misoriented superlattices studied by X-ray techniques, (PrF-MU). Besides we would like to focus our publication efforts on the study of quantum dimensional objects (QD, QW, SL) and practical aspects of the behaviour of different types of heterointerfaces.

Nahoru

Project of the Czech Science Foundation

Quantum dots in A^IIIB^V semiconductors
(1999 - 2001)
202/99/1613

in cooperation with: Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

Nahoru

Grant Agency of the Academy of Sciences of the Czech Republic Project

Surface migration and reconstruction in the kinetic of  A^IIIB^V layer growth and a new model for the calculation of the point defects concentration
(1999 - 2001)
IAA 206 7901

in cooperation with: Institute of Radio Engineering and Electronics, AS CR

The basic theory of the Burton-Cabrera-Frank (BCF) has been developed to describe the growth mechanisms when single atoms or molecules are adsorbed from its vapour, than migrate to the surface steps and along steps to the kinks. In the case of deposition A^IIIB^V compounds by Mo VPE or MBE and their modifications the situation is more complex. A rough estimate of Xs ( mean displacement before reevaporation) gives different values for different substances composing the layer and composition of adsorbed molecules, which is different for different growth condition. The aim of the project is the theoretical description of the more complex surface migration and reconstruction processes. Finally, the point defect concentration in MO VPE grown layers we will try to calculate since the LPE formalism is not sufficiently accurate at MO VPE growth condition.

Nahoru

Grant Agency of the Academy of Sciences of the Czech Republic Project

Preparation of A^IIIB^V type II Semiconductor Heterointerfaces and their Characterisation
(1998 - 2000)
A1010807

in cooperation with: Ioffe Physicotechnical Institute St. Petersburg, Russia

The idea of the project is to make use of selected physical characterisation techniques (low temperature luminescence, X-ray diffraction, Raman spectroscopy, X-ray microanalysis, scanning electron and atomic force microscopy and transport measurements) for the study and optimisation of the heterointerfaces in epitaxial layers, heterostructures, multiple quantum wells and superlattices of AIIIBV semiconductors, namely binary, ternary and quaternary compounds (in the GaSb/InAs/GaAs/AlAs systems). These structures will be prepared using the one and only LP-MOVPE machine in the Czech Republic (AIXTRON 200). The main interest will be focused on the recombination processes at heteroboundaries of type I. and type II., using photo and electroluminescence measurements and their theoretical analysis. New physical concepts for optimisation of coherent light sources for the mid infrared region (2-5microns) should be the practical results. This project will make use of the equipment and expertise gained during the work on preceding EC and GA CR projects in last four years.

Hodnocení GA AV:
Výsledky grantu jsou hodnoceny jako vynikající.

Nahoru

Post-doc Project of the Czech Science Foundation

(1998 - 2001)

Preparation and characterisation of GaSb based MOVPE epitaxial layers and structures

The aim of the project is to characterise and optimise the growth of GaSb based semiconductor layers from different precursors using Metal-Organic Vapour Phase Epitaxy (MOVPE). These materials may be suitable mainly for the preparation of detectors and laser diodes emitting in the mid-infrared range. As precursors, the following materials will be used: trimethylgallium (TMGa) or triethylgallium (TEGa), arsin (AsH3) or tertiarybutylarsin (TBAs), trimethylaluminium (TMAl) or tristertiarybutylaluminium (TTBAl) and trisdimethylaminoantimony (TDMASb) or triethylantimony (TESb), while the suitability of using the given precursors will be discussed and compared from the viewpoint of mutual compatibility during growth as well as from the viewpoint of their thermal decomposition and thus also the quality of the layer prepared. We can expect that the layers, prepared from newly developed precursors which thanks to weaker chemical bonds of metal-organic radical show lower decomposition temperature, could be of better quality than the currently prepared layers. Sample growth will be performed under various technological conditions, while specification will be gradually performed of separate layers prepared from different precursors using helium temperature photoluminescence, Hall effect, different microscopic techniques, X-ray diffraction and Raman spectroscopy.

Nahoru

European Community Project

Advanced Room Temperature Mid-infrared Antimony-based Lasers by MOVPE
ADMIRAL (1997 - 2000)
ERB INCO COPERNICUS 20 CT 97 0007 * BRITE/EURAM III - BRPR-CT97-0466

in cooperation with:

EPICHEM, Bramborough, United Kingdom
AIXTRON, Aachen, Germany
RWTH, Aachen, Germany
University of Montpellier 2, France

Detectors operating in the mid-infrared require efficient light sources, those based on antimonides will be investigated. The consortium will develop the optimum precursor system to allow MOVPE growth of laser structures. Low temperature precursors are required due to the low melting point of InSb employed in the structure. The main basic research problem is connected with the increasing role of nonradiative recombination processes with increasing operating temperature. Since the goal of the project is to approach the limits of room temperature operation, the recombination processes have to be understood in great detail. Investigation of device design and comparison with MBE material will also be performed. Monitoring for CH₄ and CO₂ in the atmosphere and in combustion engine exhaust are the main areas for final device use.

Nahoru

Grant of Ministry of Education, Youth and Sports
INCO - COPERNICUS, Activity 1&3

Support for Advanced Room Temperature Mid-infrared Antimony-based Lasers by MOVPE
(1998 - 2000)
OK312 (1998)

Nahoru

Project of the Czech Science Foundation

Research structures for Microelectronics prepared by Metalorganic Vapour Phase Epitaxy
(1996 - 1998)
102/96/1703

in cooperation with:
Charles University, Prague, Faculty of Mathematics and Physics, Dep. of Semiconductor Physics
Institute of Chemical Technology, Prague, Dep. of Solid State Engineering
Czech Technical University, Prague, Faculty of Electrical Engineering, Dep. of Microelectronic
Masaryk University, Brno, Faculty od Science, Dep. of Condensed Matter Physics

Souhrn výsledků:
Technologie tenkých polovodičových vrstev - MOVPE se ukázala jako velmi vhodná pro přípravu různých typů vzorků (kvantově-rozměrových - QD, QW, MQW a SL na bázi GaAs, GASb, InAs) pro studium základních vlastností i cílených aplikačně. Významným výsledkem KFP MFF, podle našeho názoru dokonce přesahujícím rozměr projektu, bylo zavedení speciální fotovoltaické metody k určování kvantových přechodů a defektů ve strukturách s QW. Na pracovišti VŠCHT byly teoreticky sledovány i vybrané aspekty termodynamiky epitaxního růstu konkrétních materiálů. Výsledky jsou přínosem pro optimalizaci epitaxního růstu. V rámci výzkumu technologie přípravy polovodičových optoelektronických struktur byly navrženy, realizovány a proměřeny vzorky experimentálních kanálkových vlnovodů na epitaxních heterostrukturách z GaAlAs/GaAs. Výzkum technologie přípravy kvalitních ohmických kontaktů byl řešen na vrstevnatých polovodičových strukturách A^IIIB^V. Významné jsou i poznatky o supermřížkách a vlnovodech na bázi GaAs/GaAlAs, zvláště podrobné studium jejich optických vlastností - FEL ČVUT a PřF MU.  

Hodnocení GA ČR:
V rámci projektu se 5 významných českých vědeckých pracovišť zabývalo technologiemi přípravy struktur metodou organokovové epitaxe a studiem jevů na těchto strukturách. Technologie tenkých polovodičových vrstev založená na výše uvedené metodě se ukázala vhodnou pro přípravu vzorků a studium jejich fyzikálních vlastností. Projekt významně přispěl k prohloubení vědecké spolupráce mezi specializocvanými pracovišti a umožnil školení doktorandů. Výstupem projektu bylo celkem 27 publikací. Řešitelé dodržovali pravidla a odpovědně hospodařili s přidělenými finančními prostředky. Celkově bylo řešení projektu hodnoceno jako vynikající.

Nahoru

European Community Project

Control of Enviromental Pollution by Tunable Diode Laser Absorption Spectroscopy in the Spectral Range 2 - 4 µm
(1994 - 1997)
ERB 3512 PL 940813 * (COP 813)

in cooperation with:

University of Montpellier 2, France
Ioffe Physicotechnical Institute St. Petersburg, Russia
Fraunhofer Institute, Garmisch-Partenkirchen, Germany
Institute of Electron Technology, Warsaw, Poland
IBSG, St. Petersburg, Russia

Nahoru

European Community Project

METOVAPCO (1995 - 1996)
ERB 3510 PL 92 9657
Metalorganic Vaporization Control

in cooperation with:

DAS, Dresden, Germany
Technische Universität Berlin, Germany
Warsaw University, Poland

Nahoru