Interface properties of ITO/n-Si heterojunction solar cell: Quantum tunneling, passivation and hole-selective contacts

• Published in: Solar energy Vol. 173; pp. 456 - 461
• Main Authors: Song, X.M., Gao, M., Huang, Z.G., Han, B.C., Wan, Y.Z., Lei, Q.Y., Ma, Z.Q.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01-10-2018; Pergamon Press Inc
• Subjects: a-SiOx(In); Afors-het; Band gap; Buffer layers; Computer simulation; Electric contacts; Heterojunctions; Interfacial properties; ITO/n-Si solar cells; Mathematical models; Oxygen; P-n junctions; P-type semiconductors; Passivation; Passivity; Photovoltaic cells; Photovoltaics; Quantum tunnelling; Semiconductor materials; Simulation; Software; Solar cells; Solar energy; Tunneling; Tunneling; Afors-het; ITO/n-Si solar cells; a-SiOx(In); Passivation
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2018.07.083

•Interface layer of ITO/n-Si heterojunction solar cell with a ternary-like hybrid of a-SiOx(In) is assumed to be a double stacks of 1.2 nm quasi p type semiconductor and 0.2 nm insulator.•The intermediate region behaviors as a semiconductor material with a wide band gap of 2.06 eV, which is suitable for the transport of hole and an induced quasi p-n junction.•The negative charge centers play multi-roles including field effect passivation, inducing inversion layer and acting selective contacts.•The p+-n junction induced by the work function difference of ITO (5.06 eV) and n-Si (4.35 eV) is the origin of the built-in field.
In this report, a numerical simulation for ITO/n-Si based hetero-junction (ISHJ) photovoltaic device has been carried out by using AFORS-HET software and a proper model, in which the naturally derived interface layer with a ternary-like hybrid of a-SiOx(In) is assumed to be a double stacks of 1.2 nm quasi p type semiconductor and 0.2 nm insulator as buffer layer. The negative charge centers, in the range of >1 × 1017 cm−3, associated with oxygen vacancies and indium-ion correlative ternary hybrid in the intermediate region play multi-roles, including field effect passivation, inducing inversion layer and acting selective contacts to a certain extent. The simulation results manifest that the intermediate region behaviors as a semiconductor material with a wide band gap of 2.06 eV, which is suitable for the transport of hole and an induced quasi p-n junction. Additionally, the simulated J-V curve arisen from the key opto-electric parameters of the device by the simulation agrees with the experimental one with a high fill factor of 74.2% well.