Resonant interaction of acceptor states and optical phonons in silicon

The resonance broadening of line 2 in the excitation spectrum of gallium acceptors in silicon due to near coincidence of its energy with that of the zone center optical phonons, $\text{h}\text{?}$ω₀, has been confirmed under significantly improved experimental conditions. An additional feature labeled X and line 2 are interpreted as mixed excitations of the bound-hole and the optical phonon. Under uniaxial stress, the stress induced components of line 2 which approach $\text{h}\text{?}$ω₀ become more phonon-like and get “pinned” while the components of X become bound-hole-like as they recede from $\text{h}\text{?}$ω₀, and exhibit a striking increase in intensity.