Nitride-based semiconductor heterostructures for high electron mobility transistors (HEMT) are prepared using metal-organic vapour phase epitaxy (MOVPE). Optimization of such structures requires close cooperation between sample fabrication and characterisation. Samples are investigated using optical methods (Raman, photoluminescence and cathodoluminescence spectroscopy) as well as transport methods (conductivity, Hall effect, capacitance profilometry).
Nitride semiconductors present optimal materials for high-power applications, owing to their wide bandgap, high thermal conductivity and durability. Additionally, the built-in electric field arising from their interfaces allows one to prepare structures with 2-D electron gas, whose high conductivity is employed in high-frequency devices. These transistor structures are developed by the semiconductor department under the collaboration with the On Semiconductor company in Rožnov pod Radhoštěm, Czech Republic. They are modelled, prepared using MOVPE and characterised by luminescence and transport methods. All three research groups within the Semiconductor department participate in this research − Transport theory group, Optical characterization group and Technology group.