Development of Epitaxial Lift-Off to form GaAs nanowire array membranes

Abstract: Epitaxial lift-off-layers (ELO) were developed in order to create nanowire array membranes, with the intent to pave the way for solar cells in tandem. Ultimately this thesis project focused only on growing and characterizing the ELO layers on (111)B oriented GaAs substrates with MOCVD, as this process step is not thoroughly understood in literature. In this thesis, temperature and V/III ratio dependence for planar GaAs and AlGaAs MOCVD growth on (111)B oriented substrates is shown. Specular GaAs growth is shown for V/III <20 and a temperature >800°C on exactly (111)B oriented GaAs substrates. To lower the GaAs growth temperature, 2° miscut substrates were necessary. Specular Al0.51Ga0.49As on exactly (111)B oriented wafers is demonstrated at 13.2 V/III and 800°C. Although it is not demonstrated in this thesis, the author believes that epitaxial lift-off of nanowire membrane is achievable.