Concepedia

Resonant interactions of optical phonons with acceptor continuum states in silicon

Physical review. B, Solid state · 1977 · 79 citations · 19 references

TL;DR

In silicon, the zone‑center phonon of boron at 519 cm⁻¹ and analogous phonon sidebands for boron, aluminum, and gallium lie within the excitation region to the valence‑band continuum, creating antiresonances. Fano’s theory was employed to analyze the resonant interactions. Optical‑absorption experiments reveal Breit‑Wigner‑Fano resonant interactions between acceptor continuum states and localized optical phonons, with clear antiresonances observed at 519 cm⁻¹ for boron and at 764, 962, and 989 cm⁻¹ for boron, aluminum, and gallium, respectively.

Abstract

We have performed and analyzed optical-absorption experiments which provide clear evidence of Breit-Wigner-Fano resonant interactions between the electronic continuum states of acceptors and localized excitations involving optical phonons in silicon. For boron, the 519-${\mathrm{cm}}^{\ensuremath{-}1}$ zone-center phonon lies within the region of excitation to the continuum of the ${p}_{\frac{3}{2}}$ valence band, leading to an antiresonance at that wave number. In addition, antiresonances are observed in silicon doped with boron at 764 ${\mathrm{cm}}^{\ensuremath{-}1}$, aluminum at 962 ${\mathrm{cm}}^{\ensuremath{-}1}$, and gallium at 989 ${\mathrm{cm}}^{\ensuremath{-}1}$. These numbers correspond to the one-phonon sidebands of the bound-to-bound $1{S}_{\frac{3}{2}}\ensuremath{\rightarrow}2{P}_{\frac{3}{2}}$ impurity excitations, which lie within the region of excitation to the continuum of the ${p}_{\frac{1}{2}}$ valence band. Fano's theory is used to analyze these results.