Nonpolar Cubic Iii-Nitrides: From The Basics Of Growth To Device Applications

The Molecular Beam Epitaxy (MBE) of cubic group III-nitrides is a direct way to eliminate polarization effects which may limit the performance of optoelectronic devices containing quantum well or quantum dot active regions. In this paper recent progress with the MBE of phase-pure cubic GaN, AlN and their alloys is reviewed. Refection high energy electron diffraction (RHEED) has extensively been used to adjust stoichiometric growth conditions allowing severely reducing the surface roughness of layers and optimizing the hetero-interface and structural quality of multilayer stacks. The absence of polarization fields in cubic nitride nanostructures has been demonstrated. The performance of device structures taking advantage of this property like heterojunction field effect transistors (HFET) with both normally on and normally off characteristics as well as devices to demonstrate intersubband absorption in the spectral range between 1.55 μm and the terahertz region is summarized.