Comprehensive Understanding of the Role of Emitter Layer Thickness for Metal–Oxide–Semiconductors Based Solar Cells

Achieving low-cost and high-performance solar cells based on heterojunction of metal–oxide–semiconductors with silicon (Si) is a difficult task. We herein report the development of cost-effective and efficient SnO₂/p-Si heterojunction-based solar cells using the low-temperature hydrothermal method. The fabrication of SnO₂/Si heterojunction-based solar cells is realized with various thicknesses of SnO₂ layer deposited by controlling the hydrothermal deposition time. The measurements of scanning electron microscopy, optical spectra, four-point probe conductivity, current–voltage (<italic>I–V</italic>), and capacitance–voltage (<italic>C–V</italic>) reveal that the thickness of SnO₂ emitter layer significantly influences the electrical properties and the photovoltaic performance of the devices. The best power conversion efficiency of 3.09% (<italic>J_sc</italic> = 20.28 mA/cm², <italic>V_oc</italic> = 0.312 V, and FF = 48.84%) is achieved for the solar cell having n-SnO₂ thickness of 391 nm. The experimental findings disclose that the efficiency of the cells is extremely dependent on the emitter layer thickness, which plays a vital role in determining light-harvesting characteristics and carrier collective capabilities of the cells.