Design of Impact Ionization enhanced thin film c-Si HIT solar cells

This study investigates the performance of impact ionization (ii) enhanced thin film c-si solar cells using technology computer aided design (tcad) simulations. The effect of ii concerning the electrical and optical properties of the c-si solar cell is carried out. We introduce p⁺ pocket with a high doping density of the magnitude > 10¹⁸ cm^-3 to increase the electric field near the junction to values near 1 mv/cm. Using this structure the effect of ii on key solar cell parameters like J_sc, V_oc, efficiency and quantum efficiency are investigated. The simulation results show that high doping density of p⁺ pocket enhances the current density without affecting the voltage. In addition, by varying the doping concentration of the p⁺ pocket from 10¹⁸ cm^-3 to 9×10¹⁸ cm^-3 the current density increases from 18 mA/cm² to 32 mA/cm². In addition simulation results also show that internal quantum efficiency (iqe) can reach up to 1.89 with very highly doped p+ pocket (9×10¹⁸ cm^-3).