Internal polarization electric field effects on the efficiency of InN/InxGa1-xN multiple quantum dot solar cells

•Modeling of InN/InGaN quantum dots intermediate band solar cell.•Influence of internal electric field on the optoelectronic parameters.•Hole levels contribution on the solar cell characteristics.•Impact of In concentration on the InN/InGaN solar cell efficiency. In this work, we investigate the influence of the internal electric field induced by the polarization inside the active region of the p-i-n photodiode on the characteristics of InN/InxGa1-xN quantum dots intermediate band solar cell. Considering the conduction and valence band offsets, the electron and hole energy levels have been determined by solving analytically the corresponding Schrödinger equations. The hole level, usually neglected in similar studies, is taken into account to determine all the intermediate transitions. All parameters of multiple quantum dot solar cells such as open-circuit voltage, short-circuit current density and photovoltaic conversion efficiency are determined as functions of the indium content, the internal electric field, inter-dot distances and dot sizes. Our calculations show that determining the photovoltaic conversion efficiency (η) without taking into account the internal electric field leads to an overestimation of η.