An infrared study of the shallow acceptor states in GaAs

The shallow acceptor states in gallium arsenide have been studied by far-infrared Fourier transform spectroscopy. The energy level structure observed in photoconductivity is compared with the predictions of recent acceptor state theory and the agreement is found to be generally good. The groundstate ionisation energies are found to be 26.9 meV (carbon), 28.7 meV (magnesium), 30.6 meV (zinc) and 34.8 meV (silicon). The general features of the GaAs spectra are also compared with results previously obtained for Ge by Jones and Fisher (1965) for InSb by Kaplan (1973) and deep manganese acceptors in GaAs by Chapman and Hutchinson (1967). There is strong similarity between GaAs and the other materials. This similarity extends to the Zeeman spectra and is exploited in interpreting the Zeeman components observed in GaAs in terms of theoretical predictions.