Transmission electron microscopy of strained In/sub y/Ga/sub 1//sub -//sub y/As/GaAs multiquantum wells: The generation of misfit dislocations

Journal Article · Mon May 01 00:00:00 EDT 1989 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.342654· OSTI ID:6406808

Chang, K H; Bhattacharya, P K; Gibala, R

We have investigated the generation and propagation of misfit dislocations in strained In/sub y/Ga/sub 1-//sub y/As/GaAs multiquantum wells grown by molecular-beam epitaxy, with cross-sectional transmission electron microscopy. The samples are of excellent optical quality, with multiquantum wells having well widths of 100 A, being characterized by excitonic linewidths and Stokes shifts of 1.5--2.5 and 1--2 meV, respectively. We have examined the growth of 2-..mu..m-thick multiquantum-well samples grown either directly on GaAs, or with an intermediate composition buffer layer, and for the cases of small (y = 0.07) and large (y = 0.16) misfits. It is seen that for the case of quantum wells with small misfit, grown directly on GaAs, metastable growth can be achieved. This is confirmed by low-temperature absorption measurements and from transmission electron microscopy experiments performed both before and after post-growth thermal annealing. In the case of quantum wells with large misfits directly grown on GaAs, dislocations are generated within the first few periods, and high optical quality is retained in the subsequent free-standing quantum wells. In the case of quantum wells grown with an intermediate composition In/sub x/Ga/sub 1-//sub x/As buffer layer, dislocations are generated at the buffer-GaAs interface, and the freestanding multiquantum well is again of very high quality.

• Research Organization: Department of Materials Science and Engineering, The University of Michigan, Ann Arbor, Michigan 48109
• OSTI ID: 6406808
• Journal Information: J. Appl. Phys.; (United States), Vol. 65:9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GALLIUM ARSENIDES
DISLOCATIONS
INDIUM ARSENIDES
EXCITONS
INTERFACES
LINE WIDTHS
MOLECULAR BEAM EPITAXY
POTENTIALS
STRAINS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
ARSENIC COMPOUNDS
ARSENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
EPITAXY
FILMS
GALLIUM COMPOUNDS
INDIUM COMPOUNDS
LINE DEFECTS
MICROSCOPY
PNICTIDES
QUASI PARTICLES
360602* - Other Materials- Structure & Phase Studies