Optical characterization of Zn-doped In_0.14Ga _0.86As_0.13Sb_0.87 layers grown by liquid phase epitaxy

Quaternary layers were grown by liquid phase epitaxy on (1 0 0) GaSb substrates under lattice-matching conditions. The low-temperature photoluminescence of p-type In_xGa_1-xAs_ySb _1-y was obtained as a function of incorporated zinc concentration. The photoluminescence spectra were interpreted using a model which takes into account nonparabolicity of the valence band. Calculations of the peak position and photoluminescence transitions were performed. Both the band filling as well as band tailing due to Coulomb interaction of free carriers with ionized impurities and shrinkage due to exchange interaction between free carriers were considered in order to properly account for the observed features of photoluminescence spectra. It is proposed that low-temperature photoluminescence band-to-band energy transition can be used to obtain the carrier concentration in p-type In_xGa_1-xAs_ySb_1-y. This method could be used to estimate free carrier concentration ranging from 6.036×10¹⁶ to 1.350×10¹⁸ cm^-3.