EFFECT OF HEAT TREATMENT WITH EXCESS ARSENIC PRESSURE ON PHOTOLUMINESCENCE OF P-TYPE GAAS

Photoluminescence measurements at 20°, 77°, and 300°K are used to investigate radiative recombination via the near gap transition in p-type GaAs after heat treatment with excess arsenic pressure, PAs4. The heat treatments are performed at 800°C for 24 h. For heavily doped crystals of Zn acceptor concentration NA≃5×1018 cm -3, the intensity of the Zn photoluminescent line, I(hv1), is independent of PAs4 up to pressures as high as 3 atm. For lightly doped materials of NA+ND≃8×1016 cm-3, I(hv1) ∝ (PAs4)-1/4 for PAs4 >2×10-1 atm. These results can be attributed to Ga vacancies or associates of Ga vacancies with other defects which dominate the nonradiative recombination at low acceptor concentration and to acceptor impurities which dominate the nonradiative recombination at high acceptor concentration. The transitions corresponding to shallow defect levels at 1.480 eV are found to disappear after heat treatment. © 1968 The American Institute of Physics.