Laser excitation induced photoluminescence linewidth reduction in molecular beam epitaxial InAlAs layers grown on InP substrates

✍ Scribed by S.F. Yoon; K. Radhakrishnan; Q.H. Du

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 137 KB
• Volume: 23
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1996.0442

✦ Synopsis

An experimental investigation is presented on the influence of laser excitation on the photoluminescence (PL) linewidth in InAlAs layers grown lattice matched to InP substrates by molecular beam epitaxy (MBE). Measurements performed on silicon-doped samples and samples grown at different arsenic overpressures (V/III flux ratio) showed that the linewidth decreases with increasing laser excitation power. A model describing an unbalanced migration of photo-generated charge carriers due to the presence of clusters is proposed to explain the effect of the linewidth reduction. Also, the trend of the linewidth decrease becomes more pronounced in InAlAs samples with higher silicon doping concentrations and those grown at higher V/III ratios. Samples with higher silicon-doping concentrations have broader linewidths which could be the result of poorer alloy quality due to the presence of disorder (S. F. Yoon et al., J. Appl. Phys. 78, 1812(1995)). A similar trend of linewidth reduction was observed at temperatures as high as 30 K. Our results show that such a measurement of linewidth vs. laser excitation power can be used as a supplementary method for InAlAs material characterization.