Low threading dislocation density GaAs growth on on-axis GaP/Si (001)

D. Jung, P. G. Callahan, B. Shin, K. Murherjee, A. C. Gossard, and J. E. Bowers
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RHEED patterns of (a) 10 nm thick LT-GaAs layer and (b) 100 nm thick HT-GaAs layer on GaP/Si substrate.
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Journal of Applied Physics
Volume 122, Issue 22, 225703

We report a systematic study of high quality GaAs growths on on-axis (001) GaP/Si substrates using molecular beam epitaxy. Various types of dislocation filter layers and growth temperatures of initial GaAs layer were investigated to reduce the threading dislocation densities in GaAs on GaP/Si. Electron channeling contrast imaging techniques revealed that an optimized GaAs buffer layer with thermal cycle annealing and InGaAs/GaAs dislocation filter layers has a threading dislocation density of 7.2 106 cm2 , which is a factor of 40 lower than an unoptimized GaAs buffer. The root-mean-square surface roughness was greatly decreased from 7.8 nm to 2.9 nm after the optimization process. A strong enhancement in photoluminescence intensity indicates that the optimized GaAs template grown on on-axis (001) GaP/Si substrates is a promising virtual substrate for Si-based optoelectronic devices. 


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