Influence of in doping in GaN barriers on luminescence properties of InGaN/GaN multiple quantum well LEDs

Room-temperature photoluminescence (RT PL) spectra of InGaN/GaN multiple quantum well (MQW) structures grown by metalorganic chemical vapor deposition (MOCVD) was investigated. It is found that with increasing In content in GaN barriers, the FWHM and emission intensity decreases, and the emission wavelength is first red shift and then blue shift. The shrinkage of FWHM and emission wavelength blue shift can be attributed to the reduction of piezoelectric field, and the lower height of potential barrier will make carrier confinement weaker and ground state level lower, which resulting in emission intensity decreasing and wavelength red shift. In addition, doping the barrier with In will induce more inhomogeneous and deeper localized states in InGaN QWs, which also contribute to a red shift of PL emission wavelength.