Investigation of interface quality and passivation improvement with a-SiO:H deposited by ECRCVD at low temperature

Yen Ho Chu, Chien Chieh Lee, Teng Hsiang Chang, Yu Lin Hsieh, Shian Ming Liu, Jenq Yang Chang, Tomi T. Li, I. Chen Chen

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Hydrogenated amorphous silicon oxide (a-SiO:H) is an attractive passivation material to replace hydrogenated amorphous silicon (a-Si:H) in heterojunction solar cells due to its properties of high-transparency and a wide band gap. In this study, we investigated the structural properties, optical properties, and passivation quality of a-SiO:H films by varying the ratio of [CO2]/[SiH4]. Both the optical band gap and the absorption coefficient of a-SiO:H films could be conveniently modulated by varying the CO2 partial pressure. High quality passivation with a low surface recombination velocity of approximately 17.4 cm/s can be obtained when the ratio of [CO2]/[SiH4] = 0.32, due to the suppression of partial epitaxial growth at the interface, resulting in an abrupt interface, which was verified by transmission electron microscopy. Furthermore, the optical absorption coefficient of a-SiO:H ([CO2]/[SiH4] = 0.32) decreased by 25% compared with that of the a-Si:H (without CO2) at a wavelength of 300 nm. As a result, the high passivation quality was attributed to the properties of the abrupt interface and the sufficient hydrogen content between the a-SiO:H/c-Si interface.

Original languageEnglish
Pages (from-to)5-10
Number of pages6
JournalJournal of Non-Crystalline Solids
Volume412
DOIs
StatePublished - 15 Mar 2015

Keywords

  • Chemical vapour deposition (CVD)
  • Heterostructures
  • Interfaces
  • Thin films

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