SUBBAND ENERGY STUDIES IN INTERMIXED GAAS AL0.35GA0.65AS MULTIPLE-QUANTUM WELLS/

Photoluminescence (PL) measurements were performed in order to investi gate the deformation of the GaAs/Al0.35Ga0.65As multiple quantum wells (MQWs) due to thermal treatment. Rapid thermal annealing was performe d at 950 degrees C for 10, 20, and 30s after the Si3N4 capping layer w as evaporated on the sample. The PL spectra for the as-grown and annea led samples show the transitions from the Ist electronic subband to th e Ist heavy hole (E1-HH1) and from the 2nd electronic subband to the 2 nd heavy hole (E2-HH2), and the PL signals shift to the high-energy si de as the annealing time increases. The potential profile of the quant um well as a function of the Al diffusion length was investigated, and subband energy levels in the GaAs/Al0.35Ga0.65As MQWs were calculated by a variational method making use of the potential profile. The Al d iffusion lengths for the annealed MQWs at 950 degrees C for 10, 20, an d 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 experimen tal values of (E2-HH2) and (E1-HH1) as a function of the Al diffusion length is in good agreement with theoretical results.