Optical properties and recombination dynamics of InGaN/GaN multiple quantum wells with Si-doped barriers

The effects of Si doping on the optical properties and recombination dynamics of InGaN/GaN multiple quantum wells (MQWs) has been investigated by means of photoluminescence (PL) and time-resolved PL (TRPL) measurements. The peak energies and the full width at half maximum (FWHM) values of both the stimulated emission and spontaneous emission increase with increasing Si doping concentration. The PL spectrum consisting of three (or two) Gaussian peaks was interpreted by the results of the TRPL. These PL emission peaks have three (or two) different origins (i.e., different decay times) of the first (τ1), the second (τ2), and the third (τ3) PL emission. The redshift of the emission peak with delay time and the increase of the emission peak energies and the FWHMs with increasing Si doping concentration are attributed to the band filling of localized states.