Phase separations in graded-indium content InGaN/GaN multiple quantum wells and its function to high quantum efficiency

Abstract

Phase separations have been studied for graded-indium content In xGa 1-xN/GaN multiple quantum wells (MQWs) with different indium contents by means of photoluminescence (PL), cathodeluminescence (CL) and time-resolved PL (TRPL) techniques. Besides the main emission peaks, all samples show another 2 peaks at the high and low energy parts of the main peaks in PL when excited at 10 K. CL images show a clear contrast for 3 samples, which indicates an increasing phase separation with increasing indium content. TRPL spectra at 15 K of the main emissions show an increasing delay of rising time with indium content, which means a carrier transferring from low indium content structures to high indium content structures. © 2012 Chinese Institute of Electronics.