An analysis and optimization of selective emitter with etched-back structure of crystalline silicon solar cells using TCAD simulation

This paper presents a comprehensive analysis of the characteristics of the crystalline silicon solar cell that depend on the etched-back structure of the selective emitter by TCAD simulation. The simulation results show that a solar cell with an etched-back selective emitter can have much improved cell characteristics compared to those of the a solar cell with a homogenous emitter by increasing short wavelength spectral response characteristics by decreasing its recombination rate and defect density in the lightly doped region. With the optimized heavily/lightly doped emitter region, the short circuit current (J_sc), the open circuit voltage (V_oc), the fill factor, and the conversion efficiency of the crystalline silicon solar cell with an etched-back selective emitter were 35.88 mA/cm², 638.8 mV, 78.85%, and 18.07% with 60 nm emitter etched-back depth, respectively. The etched-back structure of the selective emitter increased the short circuit current by 1.2 mA/cm² and conversion efficiency by 0.6% from those of the solar cell with a homogeneous-structure emitter, respectively. Therefore, the carrier concentration gradient in the selective emitter can be an important factor in the effective collection of minority carriers.