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We have compared the conventional high work function Pt contacts versus the less explored low work function Mg contacts to semi-insulating GaAs (S). Mg-S-Pt structure shows a significant current decrease at low bias while the Mg-S-Mg structure exhibits a saturation current at high voltages more than an order of magnitude lower with respect to the Pt-S-Pt reference. The phenomena observed are explained by the presence of insulating MgO layer at the M-S interface, as confirmed by the XPS analysis.
Description
I–V characteristics of SI GaAs based detector structures with three different contact combinations: (i) Pt-S-Pt, (ii) Mg-S-Pt, and (iii) Mg-S-Mg measured in the dark at room temperature
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