Temperature dependence of photoluminescence oxygen-related deep levels in Al0.2Ga0.3In0.5P:Be grown by solid source molecular beam epitaxy Article uri icon

abstract

  • In this work, the photoluminescence (PL) properties of Be-doped Al 0.2Ga0.3In0.5 P layers grown on GaAs by solid source molecular beam epitaxy were studied as a function of temperature. Three samples were grown varying the P-cell cracker temperature (PCT). The Be-cell temperature was 1015 °C for all samples. The 77 K PL spectra from samples show three main transitions located at 2.182, 2.162, and 2.065 eV, related to band-to-band emission (B,B), Be acceptor levels (A0,X) and oxygen deep levels (O,DL), respectively. The authors observed that for the sample grown at the highest PCT the (O,DL) transition dominates the whole 77 K PL spectra, while for the sample grown at intermediate PCT it appears with lower intensity. This peak is not observed in the PL spectra for the layers grown at PCT equal to 800 °C. The authors monitored the evolution with temperature of (O,DL) and observed that it is located from 87 to 135 meV below the conduction band when the temperature is varied from 15 to 120 K. After 120 K, this transition disappears. The NA - ND carrier concentration measured with an ECV profiler shows a diminution of the active Be doping concentration as PCT increases as a consequence of compensation of Be dopants by donorlike O traps. This phenomena is reflected in the PL properties of the samples as a reduction of the intensity of (A0,X). Also, the 300 K PL spectra for the samples shows that by increasing PCT from 800 to 1000 °C, the PL intensity of the (B,B) transition decreased dramatically due to the introduction of oxygen-related nonradiative recombination centers. © 2008 American Vacuum Society.

publication date

  • 2008-01-01