Growth temperature dependence of transport properties of InAs epilayers grown on GaP

Undoped InAs was grown by molecular-beam epitaxy directly on GaP at a set of different substrate temperatures. Transport properties were characterized by means of Hall-effect and resistivity measurements at temperatures between 3 and 300 K. It was observed that samples grown at higher temperatures had lower carrier concentrations, consistent with a decrease of ionized defects. In addition, samples grown at higher temperatures also had higher mobility, consistent with a smaller number of scattering centers. Samples grown at higher temperatures also showed much higher sensitivity of the mobility to the measurement temperature, suggesting a drop in neutral scattering defects. Transmission electron microscopy showed that the samples grown at higher temperatures had a significantly different dislocation microstructure. The observed dislocation microstructure is consistent with the mechanisms proposed for the influence of growth temperature on the variation of carrier concentration and mobility. (C) 2000 American Institute of Physics. [S0003-6951(00)01234-1].