Optical Properties of Strained AlGaN and GaInN on GaN

The composition of alloys in strained ternary alloy layers, Al x Ga 1- x N (0< x <0.25) and Ga 1- x In x N (0< x <0.20), on thick GaN was precisely determined using the high-resolution X-ray diffraction profile. The band gap of strained AlGaN is found to increase almost linearly according to the AlN molar fraction, while that of strained GaInN has a large bowing parameter of 3.2 eV.