Microstructures of (In,Ga)P alloys grown on GaAs by metalorganic vapor‐phase epitaxy
作者:
D. M. Follstaedt,
R. P. Schneider,
E. D. Jones,
期刊:
Journal of Applied Physics
(AIP Available online 1995)
卷期:
Volume 77,
issue 7
页码: 3077-3087
ISSN:0021-8979
年代: 1995
DOI:10.1063/1.358659
出版商: AIP
数据来源: AIP
摘要:
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 °C on substrates at or near (001) or (113)Ausing 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 °C and more diffuse at 600 and 725 °C due to higher densities of antiphase boundaries. Order can be eliminated by growth at 750 °C or above to obtain the highest band gaps and optical emission energies. Detailed investigation of the microstructure for growth at 675 °C indicates that ordered domains are platelets consisting of thin (1–2 nm) lamella on (001) planes that alternate between the two {111}Bordering 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 ∼100 nm. Implications of the coexistence of phase separation and ordering for growth models describing these phenomena are discussed. ©1995 American Institute of Physics.
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