Investigation of ZnMgO/µc-Si thin-film solar cell using two-dimensional numerical simulation

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Microcrystalline silicon (µc-Si) thin-film solar cells are crucial for reducing photovoltaic costs.
• Optimizing ZnMgO/µc-Si interfaces is key to enhancing solar cell efficiency.

Purpose of the Study:

• To develop and present a comprehensive numerical model for optimizing ZnMgO/µc-Si solar cells.
• To analyze the impact of various parameters on solar cell performance metrics.

Main Methods:

• A numerical model incorporating horizontal and vertical grain boundaries (GBs) with Gaussian-distributed trap states.
• Simulation of key parameters: Mg concentration, thickness, and doping in ZnMgO emitter.
• Analysis of GB-induced recombination in the µc-Si absorber.

Main Results:

• Optimal Mg concentration in ZnMgO is found to be 20%, with diminishing returns beyond this point.
• Grain boundary recombination significantly degrades performance; smaller grain sizes and higher trap densities (above 10^11 cm^-2) lead to sharp declines.
• Optimal ZnMgO emitter parameters are ~100 nm thickness and ~5x10^16 cm^-3 doping.
• A maximum simulated efficiency of ~14.3% was achieved under optimized conditions.

Conclusions:

• The developed model provides a pathway for optimizing ZnMgO/µc-Si solar cell design.
• Controlling grain boundary properties and optimizing emitter characteristics are critical for high-efficiency devices.
• The model's validation against previous results confirms its reliability for future research.