Photoluminescence and Gain of MBE Grown Cubic InxGa1—xN/GaN Heterostructures

Abstract

We report on the molecular beam epitaxy of cubic InxGa1—xN/GaN heterostructures with different In contents. High resolution X-ray diffraction (HRXRD) measurements gave the In content in the layers. Reciprocal space mapping of the symmetrical (002) and asymmetrical (113) reflection reveal that cubic InxGa1—xN with low In content (x < 0.2) is single phase whereas layers with higher In content show evidence of phase separation. The photoluminescence (PL) of the InxGa1—xN layers was measured at 2 K. The full width at half maximum of the PL is as low as 200 meV for single phase layers whereas the emission is significantly broadened for phase separated InxGa1—xN. Optical gain measurements revealed a maximum gain of about 70 cm—1 from InxGa1—xN (x = 0.07) and a decrease of the gain with increasing In content.