Microscopic structure of a VH4center trapped by C in Si

Abstract

The Si materials typically used to fabricate solar cells often contain high concentrations of carbon and hydrogen impurities. One of the more thermally stable defects in Si that contains both C and H gives rise to a Si-H vibrational line at 2184.3 cm${}^{\ensuremath{-}1}$. We show that this center also gives rise to additional weak Si-H and C-H lines at 2214.4 and 2826.9 cm${}^{\ensuremath{-}1}$ (4.2 K). When D is partially substituted for H, rich isotopic splittings of these IR lines are produced. An analysis of these data reveals that the 2184.3, 2214.4, and 2826.9 cm${}^{\ensuremath{-}1}$ lines are due to a VH${}_{4}$ defect bound to a substitutional C impurity, i.e., a VH${}_{3}$-HC center.