Microstructures of (In,Ga)P alloys grown on GaAs by metalorganic vapor-phase epitaxy
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1056 (United States)
The microstructures of metalorganic vapor-phase epitaxy alloys of (In,Ga)P grown on GaAs substrates were examined using transmission electron microscopy. Alloys examined were grown at 600--775 [degree]C on substrates at or near (001) or (113)[sub A] using growth rates of 0.69 and 0.17 nm/s. Two common semiconductor alloy phenomenon, ordering and phase separation, were studied over this range of growth conditions. The CuPt-type ordering reflections are sharpest for growth at 675 [degree]C and more diffuse at 600 and 725 [degree]C due to higher densities of antiphase boundaries. Order can be eliminated by growth at 750 [degree]C or above to obtain the highest band gaps and optical emission energies. Detailed investigation of the microstructure for growth at 675 [degree]C indicates that ordered domains are platelets consisting of thin (1--2 nm) lamella on (001) planes that alternate between the two [l brace]111[r brace][sub B] ordering variants, in agreement with a model proposed by others. We have formed unicompositional'' quantum wells with sharply defined ordered layers between disordered barrier layers by changing growth temperature, which demonstrates that ordering is determined to a great degree by the conditions during growth. Phase separation is seen for the entire range of growth parameters, independently of ordering; its contrast shows modulations with a variable spacing ranging from a few nanometers to [similar to]100 nm. Implications of the coexistence of phase separation and ordering for growth models describing these phenomena are discussed.
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 6565894
- Journal Information:
- Journal of Applied Physics; (United States), Vol. 77:7; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ordering and phase separation in MOCVD InGaP alloys and unicompositional quantum wells
The initial stages of growth of CuPt{sub B} ordered Ga{sub 0.52}In{sub 0.48}P/GaAs and Ga{sub 0.47}In{sub 0.53}As/InP
Related Subjects
GALLIUM PHOSPHIDES
VAPOR PHASE EPITAXY
INDIUM PHOSPHIDES
GRAIN BOUNDARIES
MICROSTRUCTURE
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
ELECTRON MICROSCOPY
EPITAXY
GALLIUM COMPOUNDS
INDIUM COMPOUNDS
MICROSCOPY
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PNICTIDES
360602* - Other Materials- Structure & Phase Studies