Transport Behaviour in Low-Resistance Metal/p-GaAs Interfaces

Low temperature current transport of Sn-GaAs contacts

We measure low temperature current transport properties of superconducting Sn contacts to pf-GaAs. For contacts alloyed at 450 C, the current-voltage characteristics show a strong dependence on alloying time. The critical temperature of Sn near the superconductor-semiconductor interface decreases from 3.8 to 1.8 K as the alloying time increases from 0 to 120 s. On the other hand, a long-time al...

Spin transport through GaAs/GaMnAs/GaAs

This work addresses spin-dependent transport in the heterostructure p-GaAs/GaMnAs/p-GaAs. The diluted ferromagnetic semiconductor GaMnAs layer behaves, within mean field approximation, as a potential well for spin-down carriers and a potential barrier for spin-up ones. Thus the transport would be spin-dependent. The goal of this work is to devise spin filters relevant for spin-dependent optoele...

Capacitance-Voltage Characterization of GaAs-Oxide Interfaces

Raman Spectroscopic Studies of ZnSe/GaAs Interfaces

ZnSe/semi-insulating GaAs interfaces have been studied by observing Photogenerated plasmon – LO (PPL) coupled modes by non-resonant microRaman spectroscopy. The effect of the carriers generated by the focused laser beam was investigated for a series of different thicknesses of ZnSe epitaxial layers. The PPL mode in GaAs is observed in micro-Raman spectra for all samples, but with different magn...

SPIN TRANSPORT MEASUREMENTS IN GaAs QUANTUM DOTS

This thesis explores the spin dynamics of lateral quantum dots in GaAs/AlGaAs heterostructures, including the first demonstration of a geometry capable of measuring mesoscopic spin currents. The term “quantum dot” as used in this thesis refers to partiallyconfined regions connected to two leads by quantum point contacts. Because the quantum dots investigated in these experiments are gate-tunabl...