Heteroepitaxy of Doped and Undoped Cubic Group III-Nitrides

Cubic group III-nitrides (GaN, InN, AlN and their alloys) have a higher crystal symmetry than their thermodynamic stable hexagonal counterparts. They are expected to offer some technological advances such as easy cleaving of laser facets, easier doping and contacting. However, their metastable crystal configuration is a serious challange for crystal growth. We review recent progress made with the epitaxy and the evaluation of a number of physical properties of c-III-nitrides. We are guided by the fact that most research has been concentrated on c-GaN and that this material is the most advanced compound of all c-III-nitrides. The structural, optical and electrical properties of c-GaN as well as that of InGaN and AlGaN containing modest amounts of In and Al are discussed with regard to possible future optoelectronic device applications.