Reactive Molecular-Beam Epitaxy for Wurtzite GaN

Abstract

A1N, GaN, and InN are very promising materials for use in optoelectronic and high-temperature electronic devices. These materials and their ternary and quaternary alloys cover an energy bandgap range of 1.9–6.2 eV, suitable for band-to-band light generation with colors ranging from red to ultraviolet (uv), with wavelengths ranging from 650 to 200 nm. On the device front, they are suitable for example for negative electron-affinity cold cathodes, electronic devices, surface acoustic wave devices, uv detectors, Bragg reflectors and waveguides, uv and visible light-emitting diodes (LEDs), and laser diodes (LDs) for digital data read-write applications. Stifled by the absence of native substrates, growth and doping of high-quality III-V-nitride thin films, particularly p-type, have been major obstacles for developing GaN-based devices. Development of electronic devices such as modulation-doped field-effect transistors (MODFETs) and opto-electronic devices such as LEDs and LDs has also proven challenging.