Lateral modulation-doped structures of aluminum-gallium arsenide/gallium arsenide grown by selective area liquid-phase epitaxy

The focus of this thesis is the fabrication and characterization of the two-dimensional electron gas (2DEG) in lateral modulation-doped structures of Al{dollar}sb{lcub}rm x{rcub}{dollar}Ga{dollar}sb{lcub}1-rm x{rcub}{dollar}As/GaAs. The growth is carried out in a liquid phase epitaxy system, and the devices are characterized using high magnetic field transport at 4.2K. The thesis is divided into three parts: Chapter 1 describes the growth system and the details of growth by liquid phase epitaxy. Chapter 2 presents experiments on planar heterostructures. These experiments demonstrate the quality of the 2DEG in planar modulation-doped structures fabricated by liquid phase epitaxy by the reproducible observation of the quantum Hall effect. Chapter 3 covers the selective epitaxy experiments by describing the fabrication of the lateral modulation-doped structure by regrowth of n-Al{dollar}sb{lcub}rm x{rcub}{dollar}Ga{dollar}sb{lcub}1-rm x{rcub}{dollar}As on a patterned GaAs epilayer. The etchback action of the growth melt is shown to play an important role in the formation of the 2DEG. The application of the fabrication technique to the realization of quantum well wires and of lateral double-barrier resonant tunneling diodes is also investigated.