Influence of wetting layers on the electric potentials and optical properties of InGaN quantum dots

This study investigates the influence of wetting layers (WLs) on the electric potentials and electronic structures of InGaN quantum dots (QDs). The single particle electron and hole energies of QDs with different thicknesses and indium compositions of the WLs are calculated using the four-band k . p Hamiltonian. Numerical results show that there is an average of 60 mV increase in the maximum electric potential drop per every 0.2 nm increment in the thickness of the WL or per every 0.05 increase in indium composition α of the WL. Consequently, the transition energy decreases significantly with increasing thickness and/or indium composition of the WL. We find that the strained bandgap shifts down by 125 meV leading to a 128 meV decrease in the transition energy per every 0.4 nm increment in the thickness of the WL, which corresponds to 5.6% and 4.8% of the strained bandgap and the transition energy, respectively, for the cases without the WL. Furthermore, there is also a 32.5 meV transition energy decrease per every 0.025 increase in indium composition α of the WL. Hence, it is important to consider the thickness and indium composition of the WL in the analysis of InGaN QDs