Temperature dependence of the photoluminescence of Zn-doped In0.32Ga0.68P grown on GaAs0.61P0.39 substrates

[[abstract]]The photoluminescence (PL) spectra of Zn-doped In0.32Ga0.68P epitaxial layers grown on GaAs0.61P0.39 substrates by liquid-phase epitaxy has been investigated in the temperature range of 8-300 K. The radiative recombination processes of the direct In0.32Ga0.68P alloys for which the composition is near the direct-indirect band gap crossover point have been studied at various temperatures. At higher temperatures (> 150 K) only one emission band corresponding to free-electron-to-free-hole transition dominates. Two peaks and one broad band are observed in the PL spectrum when the temperature is below 100 K. The peak denoted by A is due to direct interband radiative recombination. The temperature dependence of the band gap in In0.32Ga0.68P layers can be expressed as 2.25 - [1.79 x 10(-3)T2/(T + 1236)] eV. The peak denoted by B, exhibited by undoped or moderately Zn-doped (p less-than-or-equal-to 3 x 10(18) cm-3) InGaP samples, is attributed to the conduction-band-to-acceptor transition. A third broad band (C) dominates at low temperatures. The maximum shifts toward shorter wavelengths as the temperature is further lowered. It is the indirect donor-acceptor pair recombination from the unidentified deep donor levels associated with indirect X(c) minima via Zn acceptor levels.[[fileno]]2030154010112[[department]]電機工程學