THIN STRUCTURE IN GALLIUM-ARSENIDE PHOTOLUMINESCENCE SPECTRA OF EXCITON AND IMPURITY STATES

Thin structure of semiinsulated GaAs photoluminescence (PL) spectra (4.2 K) has been first registered. It is determined by specific technological features and consists of doublets and triplets. Carbon is the basic background impurity in such materials as GASC-3 (GaAs substrate grown by the Chzocralski method), GASC-4, GASC-5 and traditional GaAs(Cr), but quality GASC-4 is essentially lower than that of the other ones. The components of thin structure are stimulated by radiative recombination of free holes on a shallow neutral donor with ionization of about 5 meV, by excitons bounded on C0As neutral acceptors and also by the donor-acceptor pairs, where C0As and perhaps Zn0As are the acceptors. It is shown that the both impurities are in the 1S3/2 state with ionization energy of 26.5 meV for C0Aa and 30.2 meV for Zn0As. The PL intensity redistribution between thin structure lines caused by recombination channels with the increase of excitation level was discovered. The lux-intensity characteristic for different radiation transitions are investigated and compared with the theory.