Subband energy studies in intermixed [formula omitted] multiple quantum wells

Abstract

Photoluminescence (PL) measurements were performed in order to investigate the deformation of the GaAs Al 0.35Ga 0.65As multiple quantum wells (MQWs) due to thermal treatment. Rapid thermal annealing was performed at 950°C for 10, 20, and 30 s after the Si 3N 4 capping layer was evaporated on the sample. The PL spectra for the as-grown and annealed samples show the transitions from the 1 st electronic subband to the 1 st heavy hole (E1-HH1) and from the 2nd electronic subband to the 2nd heavy hole (E2-HH2), and the PL signals shift to the high-energy side as the annealing time increases. The potential profile of the quantum well as a function of the Al diffusion length was investigated, and subband energy levels in the GaAs Al 0.35Ga 0.65As MQMs were calculated by a variational method making use of the potential profile. The Al diffusion lengths for the annealed MQWs at 950°C for 10, 20, and 30 s determined from the (E1-HH1) PL peaks were 2.15, 4.45, and 6.3 nm, respectively. The behavior of the difference between the experimental values of (E2-HH2) and (E1-HH1) as a function of the Al diffusion length is in good agreement with theoretical results.