ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Interdiffusion has been investigated in molecular-beam epitaxially (MBE)-grown, highly strained In0.35Ga0.65As/GaAs multiple quantum well (MQW) structures. Thermal intermixing and impurity-free interdiffusion (IFID) was induced via rapid thermal annealing (RTA) at temperatures between 700 and 950 °C using GaAs proximity caps and electron-beam evaporated SiO2 cap layers, respectively. Both reduced photoluminescence (PL) linewidths and increased PL intensities were observed following interdiffusion-induced band-gap shifts ranging from 6 to 220 meV. PL microscopy (PLM) investigations were utilized to study the onset of strain relaxation due to dislocation generation. Two types of line defects were found in the proximity-cap annealed samples, depending on the annealing temperature and the number of QWs: misfit dislocations with the dislocation lines parallel to 〈110〉 directions and 〈100〉-oriented line defects. No dislocations were observed in the SiO2-cap annealed samples over the entire temperature range investigated here. Resonant Raman scattering measurements of the 1LO/2LO phonon intensity ratio were used for a semiquantitative assessment of the total defect densities, including point defects (PDs). Whereas increasing PD densities and the formation of line defects were observed in the proximity-capped samples as the annealing temperature was increased, no deterioration of the structural quality due to an increased PD density was observed in the case of the SiO2-cap annealed samples. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.361503
