ABSTRACT
Photoluminescence (PL) measurements were performed in order to investigate the deformation of the GaAs/Al0.35Ga0.65As multiple quantum wells (MQWs) due to thermal treatment. Rapid thermal annealing was performed at 950°C for 10, 20, and 30 sec after the Si3N4 capping layer was evaporated on the sample. The PL spectra for the as-grown and annealed samples show the transitions from the 1st electronic subband to the 1st 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/Al0.35Ga0.65As MQWs were calcualted 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 sec 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.
