Characterization of GaAs films grown by metal organic chemical vapor deposition.

We studied undoped GaAs films grown by metal organic chemical vapor deposition in a vertical geometry atmospheric pressure reactor. Our results on the surface morphology, carrier concentration and conductivity type and low temperature photoluminescence spectra of the films, studied as a function of substrate temperature and As/Ga flux during growth, are generally in agreement with previous studies. In addition, we also report the effect of rotation speed of the substrate during growth. It is found that lower speeds give higher defect density and less n-type or even p-type and most notably enhances a defect exciton line at 1.5119eV.