Analysis of Output Power Degradation for Tunnel Metal–Insulator–Semiconductor Solar Cell

Abstract

A tunnel metal–insulator–semiconductor (MIS) solar cell with an n-type substrate is analyzed by a one-dimensional numerical simulation. The degradation of the maximum output power with the increase in interfacial layer thickness is caused by minority carrier injection into the quasi-neutral region with both optically induced forward bias and applied forward bias. This prevents the photogenerated minority carriers from diffusing from the quasi-neutral region to the depletion region edge. The resultant shortage of minority carrier supply on the semiconductor surface decreases the current extracted from the semiconductor. The obtained concave upward output characteristics under illumination, which are the main reason for the significant degradation of the fill factor, strongly depend on the saturation of the amount of injected minority carriers. The simulation also reveals that, when either interface state density or metal work function is increased, the above degradation can be improved.