ACTA

Stimulated Emission in InGaN/GaN Multiple Quantum Wells with Different Indium Content

S. Miasojedovas^a, S. Juršėnas^a, G. Kurilčik^a, A. Žukauskas^a, M. Springis^b, I. Tale^b and C.C. Yang^c
^aInstitute of Materials Science and Applied Research, Vilnius University, Saulėtekio al. 9, Building III, 10222 Vilnius, Lithuania
^bInstitute of Solid State Physics, University of Latvia, Kengaraga iela 8, Riga, 10363, Latvia
^cGraduate Institute of Electro-Optical Engineering and Department of Electrical Engineering, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei, Taiwan, R.O.C

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Received: 22 08 2004;

We report on high-excitation luminescence spectroscopy of In_xGa_1-xN/GaN multiple quantum wells with a high indium content (x=0.22÷0.30). High excitation conditions enabled us to achieve screening of built-in field by free carriers. This allowed for the evaluation of the influence of the band potential fluctuations due to variation in In-content on optical properties. Enhanced spontaneous emission was found for x≥0.22 due to carrier localization within the chaotic band potential. Meanwhile the stimulated emission was found to be the highest for structures with x≈ 0.25-0.27. We attribute the In-content dependence of the stimulated emission intensity to a trade-off between an increased carrier density and a decrease in the density of states.

DOI: 10.12693/APhysPolA.107.256
PACS numbers:78.45.+h, 78.47.+p, 78.67.De