Digitale Medien
Springer
Czechoslovak journal of physics
49 (1999), S. 823-832
ISSN:
1572-9486
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Abstract The photoluminescence (PL) spectra of n- and p-type Al x Ga1−x As (x 〉 0.42) grown by metalorganic vapor phase epitaxy (MOVPE) and liquid phase epitaxy show typically a broad PL band (BB) centered about 300 meV below the near band-gap PL lines. In the MOVPE grown samples the BB is composed out of four lines. The BB intensity increases with the doping level and dominates the spectrum at concentrations 〉 1017 cm−3. The temperature dependence of the BB intensity shows two distinct maxima at ≍ 19 K and ≍ 80 K. Hydrogenation of MOVPE grown samples at 170°C reveal an effective passivation of the shallow acceptors and the centers associated with the BB line. On the contrary hydrogenation at temperatures 〉 250°C leads to an increase in the BB intensity which is related with the evaporation of As from the surface and the generation of VAs in the layers at these temperatures. Our results suggest that the BB is related with isoelectronic centers formed when VAs and CAs or SiAs associate to form next nearest neighbor ion pairs. The PL is then due to a recombination of excitons in analogy to the case of (Zn,O) isoelectronic complexes in GaP.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1021249409817
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