Optical Spectroscopy of Ingan Epilayers in the Low Indium Composition Regime

• Published in: MRS Internet journal of nitride semiconductor research 2000, Vol.5 (S1), p.717-724
• Main Authors: Crawford, M. H., Han, J., Banas, M. A., Myers, S. M., Petersen, G. A., Figiel, J. J.
• Format: Article
• Language: English
• ISSN: 1092-5783; 1092-5783
• DOI: 10.1557/S1092578300004981

Photoluminescence (PL) spectroscopy was carried out on a series of Si-doped bulk InGaN films in the low indium (In) composition regime. Room temperature PL showed a factor of 25 increase in integrated intensity as the In composition was increased from 0 to 0.07. Temperature dependent PL data was fit to an Arrhenius equation to reveal an increasing activation energy for thermal quenching of the PL intensity as the In composition is increased. Time resolved PL measurements revealed that only the sample with highest In (x=0.07) showed a strong spectral variation in decay time across the T=4K PL resonance, indicative of recombination from localized states at low temperatures. The decay times at room temperature were non-radiatively dominated for all films, and the room temperature (non-radiative) decay times increased with increasing In, from 50-230 psec for x=0-0.07. Our data demonstrate that non-radiative recombination is less effective with increasing In composition.