Influence of InGaN growth rate on the localization states and optical properties of InGaN/GaN multiple quantum wells

摘要

The localization effect is studied in blue-violet light emitting InGaN/GaN multiple quantum wells (MQWs) with varying InGaN growth rate. The temperature-dependent photo-luminescence (PL) measurement shows that for higher-growth-rate samples two emission peaks appear in their PL spectra. Further analysis reveals that two different localization luminescence states (i.e., deep and shallow localization states) exist in the InGaN QWs with higher QW growth rate, and the competition of radiative recombination between the two localization states determines the relative intensity of the two emission peaks. It is also found that, as InGaN growth rate reduces, the deep localization state depth is almost unchanged while the shallow localization state weakens. When the QW growth rate reduces to a certain value, the shallow localization state disappears and only a single main peak induced by deep localization state appears in the PL spectra. Finally, it is noted that an intermediate InGaN growth rate results in a better light emission efficiency of the MQW.