First-principles calculations of thermal electron emission from H$^-$ in silicon

Abstract

Thermal electron emission process of a hydrogen impurity is an important topic of fundamental semiconductor physics. Despite of decades-long study, theory is not established yet. Here, we study the process of $\mathrm{H}^{-}$ in silicon, $\mathrm{H^{-}} \to \mathrm{H^{0}} + e^{-}$, using a first-principles calculation. Our calculation indicates that the process consists of two steps: slow diffusion of H$^{-}$ from a tetrahedral site to a bond-center site, which is the rate-limiting step, and faster nonradiative transition from $\mathrm{H}^{-}$ to $\mathrm{H}^{0} + e^{-}$ that occurs subsequently at the body-center site. The calculated rate is consistent with a deep level transient spectroscopy experiment