Spatially‐resolved photoluminescence study of high indium content InGaN LED structures

Abstract

AbstractSpatially and spectrally resolved photoluminescence (PL) of green light‐emitting diode (LED) structure with InGaN multiple quantum wells was studied using confocal and scanning near field optical microscopy techniques. Inhomogeneous distribution of PL intensity on the scale of 200 nm has been observed. The PL bands peaked at approximately 492 nm and 502 nm in bright and dark areas, respectively. The spot‐to‐spot variation of the peak position of the main PL band was in the range of ∼30 nm for the bright and ∼50 nm for the dark areas. The highest PL intensity in the bright areas was observed in the spots with PL band peaked at ∼492 nm, while emission intensity in dark areas had no correlation with the PL band spectral position. The inhomogeneous PL intensity distribution is explained by inhomogeneous distribution of nonradiative recombination centers, in contrast to a fairly constant tail states density (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)