Growth of Al<i>x</i>Ga1−<i>x</i>N:Ge on sapphire and silicon substrates

Abstract

AlxGa1−xN were grown on (00.1) sapphire and (111) silicon substrates in the whole composition range (0≤x≤1). The high optical quality of the epilayers was assessed by room-temperature optical absorption and photoluminescence measurements. Layers with higher Al composition are more resistive. Resistive AlxGa1−xN epilayers were successfully doped with Ge and free-electron concentration as high as 3×1019 cm−3 was achieved.