Spatio-time-resolved cathodoluminescence studies on the Si-doping effects in high AlN mole fraction AlxGa1?xN multiple quantum wells grown on an AlN template by metalorganic vapor phase epitaxy

In order to understand the reason why doping with Si in the “wells” enhanced the NBE emission efficiency, STRCL measurements and 1D-SCSP calculations were carried out on the Al_0.68Ga_0.32N / Al_0.77Ga_0.23N MQWs with different Si-doped layers. The increase in τNR, i.e decrease in the concentration of NRCs, by the Si-doping in the wells were correlated with improved lateral uniformity of the QW transition energy, which is most likely caused by the increase in the terrace width during the growth. The results suggest the importance of H₃SiNH₂ doping-reactant formation that provides wetting conditions thanks to the surface Si-N bonds and simultaneously gives rise to enhanced decomposition of NH₃, both of which lower the total energy and reduce the concentration of NRCs composed of cation vacancies.