Abstract
Control of the oxidation process is one key issue in producing high-quality emitters for crystalline silicon solar cells. In this paper, the oxidation parameters of pre-oxidation time, oxygen concentration during pre-oxidation and pre-deposition and drive-in time were optimized by using orthogonal experiments. By analyzing experimental measurements of short-circuit current, open circuit voltage, series resistance and solar cell efficiency in solar cells with different sheet resistances which were produced by using different diffusion processes, we inferred that an emitter with a sheet resistance of approximately 70 Ω/□ performed best under the existing standard solar cell process. Further investigations were conducted on emitters with sheet resistances of approximately 70 Ω/□ that were obtained from different preparation processes. The results indicate that emitters with surface phosphorus concentrations between 4.96 × 1020 cm−3 and 7.78 × 1020 cm−3 and with junction depths between 0.46 μm and 0.55 μm possessed the best quality. With no extra processing, the final preparation of the crystalline silicon solar cell efficiency can reach 18.41%, which is an increase of 0.4%abs compared to conventional emitters with 50 Ω/□ sheet resistance.
Highlights
The quality of the emitter has an important effect on the efficiency of a solar cell because the p-n junction is the core of the crystalline silicon (c-Si) solar cell
By analyzing experimental measurements of short-circuit current, open circuit voltage, series resistance and solar cell efficiency in solar cells with different sheet resistances which were produced by using different diffusion processes, we inferred that an emitter with a sheet resistance of approximately 70 / performed best under the existing standard solar cell process
The final preparation of the crystalline silicon solar cell efficiency can reach 18.41%, which is an increase of 0.4%abs compared to conventional emitters with 50 / sheet resistance
Summary
The quality of the emitter has an important effect on the efficiency of a solar cell because the p-n junction is the core of the crystalline silicon (c-Si) solar cell. Emitters in industrialized p-type c-Si solar cells are produced primarily by the method of high-temperature phosphorus (P) diffusion, and the factors that affect emitter quality include the surface P concentration and the junction depth of the emitter. The P atoms in the “dead layer” is electrically inactive Instead, they form recombination centers that increase the Auger recombination and cause the saturation current density to increase.[3,4] Simultaneously, the quantum efficiency in the blue wavelength range becomes poor and the short-circuit current (Jsc) is reduced. A high surface P concentration can result in high composite current density of the emitter, which reduces the passivation effect and lowers the open circuit voltage (Voc).[5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
