Origin of the blueshift of photoluminescence in a type-II heterostructure
1 RIES, Hokkaido University, Kita-21, Nishi-10, Sapporo, 001-0021, Japan
2 Japan Society for the Promotion of Science (JSPS), 1-8, Chiyoda-ku, Tokyo, 102-8472, Japan
3 Japan Science and Technology Corporation (CREST), Saitama, 332-0012, Japan
4 Photonic Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
Nanoscale Research Letters 2012, 7:654 doi:10.1186/1556-276X-7-654Published: 27 November 2012
Blueshifts of luminescence observed in type-II heterostructures are quantitatively examined in terms of a self-consistent approach including excitonic effects. This analysis shows that the main contribution to the blueshift originates from the well region rather than the variation of triangular potentials formed in the barrier region. The power law for the blueshift, ΔEPL ∝ Plaserm, from m = 1/2 for lower excitation Plaser to m = 1/4 for higher excitation, is obtained from the calculated results combined with a rate equation analysis, which also covers the previously believed m = 1/3 power law within a limited excitation range. The present power law is consistent with the blueshift observed in a GaAsSb/GaAs quantum well.