AbstractMBE-grown epitaxial GaN deposited at 700°C on {001}, {111}A and B GaAs has been characterised using the combined techniques of transmission electron microscopy (TEM) and photoluminescence (PL). On both { 111 } A and 111 B GaAs substrates, single crystal wurtzite GaN was formed, but with very high densities of threading defects. Best epitaxy occurred on 111B GaAs in accordance with PL measurements. An amorphous phase was identified at the GaN/{ 111 }A GaAs interface and the GaN epilayer evolved in this instance with the same Nterminated growth surface as for the case of growth on 111 B GaAs, as determined by convergent beam electron diffraction (CBED). Growth on {001} GaAs produced highly faulted columnar grains of zincblende GaN. Conversely, growth on {001} GaAs under an additional arsenic flux at 700°C resulted in the deposition of single crystal zincblende GaN with a high density of stacking faults and microtwins. Thus, the microstructure of epitaxial GaN depends very much on the detailed growth conditions and substrate orientations used.

Xin, Y., Brown, P. D., Boothroyd, C. B., Preston, A. R., Humphreys, C. J., Cheng, T. S., Foxon, C. T., Andrianov, A. V., & Orton, J. W. (1996). TEM and PL characterisation of MBE-grown epitaxial GaN/GaAs. MRS Proceedings, 423.