High Electric Field Sensing in Ultrathin SiO₂ and Tunnel Region to Enhance GaInP/Si Dual Junction Solar Cell Performance

The Si material is widely used by the manufacturers for sensing applications, because of its abundance. Better carrier sensing capability provide high performance. Solar cell is a sensor, which can sense the sun spectrum to convert it into electrical energy. This paper presents enhancement of passivation quality of GaInP/Si dual junction solar cell by enhancing the carrier transport through tunnel oxide. Reducing the SiO
₂
thickness increases the transport channel, thereby increasing the electric filed. This enhanced electric field accelerates the carrier transport in the passivation layer, and ultimately the passivation quality improves due to enhanced carries. The high electric field sensing accelerates the majority carriers towards the rear surface. Here, the improvement of the passivation quality is achieved via scaling down the oxide thickness as explained in the MIS tunneling theory. Reduction in oxide thickness provide more transport channels for the carriers, hence improves the tunneling process. Improved carrier sensing in 300nm-1100nm wavelength range, can progress towards the thermodynamic limit of open circuit voltage (
${V}_{\textit {oc}}$
). Also, we have used a wide-bandgap tunnel junction to electrically connect two cells, to see the effect on spectrum loss. The thickness and doping concentration of the tunnel junction plays very important role in tunneling process. Sharp edges and fast tunneling of the tunnel junction is the key element in proper current matching process. Numerical analysis of tunnel oxide thickness variation and wide-bandgap tunnel junction is done to obtain the optimum efficiency of 36.22% under 1-Sun concentration.