Optical absorption and photovoltaic performance in InN/InGaN multilayer quantum dots: Effects of confinement, in-fraction, and built-in electric field

This study investigates the impact of the confinement potential, indium fraction, and internal electric fields on the optical and photovoltaic properties of multilayer InN/InGaN quantum dots. Using the effective mass approximation and a variational method to solve the Schrödinger equation, we analyze how core, shell dimensions, and In-fraction variations affect energy levels, absorption spectra, and solar cell performance. The results show that increasing In-fraction in the inner layer lowers carrier energy levels due to reduced confinement, particularly in structures with small core radii. A thinner initial shell enhances the photocurrent and energy-conversion efficiency. The calculated absorption coefficients exhibit a blue shift with increasing core and shell size, confirming strong quantum confinement effects. Furthermore, stronger confinement and internal electric fields lead to higher energy absorption peaks with reduced intensity. These findings highlight the potential of optimized InN/InGaN quantum dot architectures for efficient optoelectronic and photovoltaic applications.