Optical characterization of InGaN/GaN quantum well structures with Si-doped barriers

Abstract

Summary form only given. The effect of Si doping on the optical properties of GaN and InGaN/GaN quantum well structures has recently attracted attention in relation to the optimization of light emitters based on GaN. The most striking effect of Si doping is the increase of the near band edge emission efficiency in GaN epilayers and multiple quantum well structures (MQWs). In GaN and InGaN epilayers the effect of Si doping was explained as being due to the competition between nonradiative trapping and trapping at donor levels, and to strain relief with the inclusion of Si atoms. Si doping in the barriers of InGaN/GaN MQWs has also been associated with improved interface uniformity and screening of the strain-induced piezoelectric field. In the present work we explain the effect of Si doping by the compensation of deep states and enhanced role of shallow levels due to the diffusion of dopant atoms into the well material. The optimum doping level is obtained for MQWs with parameters typical for light emitting devices.