Low temperature back-surface-field contacts deposited by hot-wire CVD for heterojunction solar cells

• Published in: Thin solid films Vol. 516; no. 20; pp. 6782 - 6785
• Main Authors: Muñoz, D., Voz, C., Martin, I., Orpella, A., Alcubilla, R., Villar, F., Bertomeu, J., Andreu, J., Roca-i-Cabarrocas, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 30.08.2008; Elsevier Science
• Subjects: Applied sciences; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Cèl·lules solars; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Ellipsometry; El·lipsometria; Energy; Exact sciences and technology; Heterostructure; Hot-wire deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Natural energy; Passivation; Photoconduction and photovoltaic effects; photodielectric effects; Photovoltaic conversion; Physics; Solar cell; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Solar cell; Heterostructure; Hot-wire deposition; Passivation; Ellipsometry; Solar cells; Buffer layer; Hot filament chemical vapor deposition; Temperature distribution; Amorphous thin film; Spectroscopic ellipsometry; Visible spectra; Frequency conversion; Quantum yield; Steady state; Double heterojunction; Thin films; Wafers; Boron additions; Microstructure; Photoconductivity; IV characteristic; Heterostructures
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.12.020

The growing interest in using thinner wafers (< 200 μm) requires the development of low temperature passivation strategies for the back contact of heterojunction solar cells. In this work, we investigate low temperature deposited back contacts based on boron-doped amorphous silicon films obtained by Hot-Wire CVD. The influence of the deposition parameters and the use of an intrinsic buffer layer have been considered. The microstructure of the deposited thin films has been comprehensively studied by Spectroscopic Ellipsometry in the UV–visible range. The effective recombination velocity at the back surface has been measured by the Quasi-Steady-State Photoconductance technique. Complete double-side heterojunction solar cells (1 cm 2) have been fabricated and characterized by External Quantum Efficiency and current–voltage measurements. Total-area conversion efficiencies up to 14.5% were achieved in a fully low temperature process (< 200 °C).