Abstract
The temperature dependence of photoluminescence from the Mg-doped In <sub>0.5</sub> Ga <sub>0.5</sub> P layers on (100) GaAs substrates grown by liquid-phase epitaxy has been studied. At low temperature, the spectra show only two major emission peaks involving intrinsic recombination and conduction-band-to-acceptor transition. The intrinsic recombination dominates in the doping concentration range studied (1.0×10 <sup>17</sup> -7. 0×10 <sup>18</sup> cm <sup>-3</sup> ) above 60 K. Below 50 K, these two peaks merged with each other when the doping concentration is higher than 1×10 <sup>18</sup> cm <sup>-3</sup> . The temperature dependence of band gap in In <sub>0.5</sub> Ga <sub>0.5</sub> P layers determined from the photoluminescence peak energy varies as 1.976 - [7.5 ×10 <sup>-4</sup> T <sup>2</sup> /(T + 500)] eV. For the moderately doped concentration (p < 1.4 × 10 <sup>18</sup> cm <sup>-3</sup> ), the Mg acceptor ionization energy obtained from 50-K photoluminescent spectra is in the range from 37 to 40 meV.