GROWTH AND TRANSPORT-PROPERTIES OF INAS THIN-FILMS ON GAAS

High-quality InAs epitaxial layers have been grown on (1 0 0) oriented semi-insulating GaAs substrates by MBE. The transport properties of l argely lattice mismatched InAs/GaAs heterojunctions have been investig ated by Hall effect measurements down to 10 K. In spite of a high disl ocation density at the heterointerface, very high electron mobilities are obtained in the InAs thin films. By doping Si into the layer far f rom the InAs/GaAs interface, we found that the doped samples have high er electron mobility than that of the undoped samples with the same th ickness. The mobility demonstrates a pronounced minimum around 300 K f or the undoped sample. But for Si-doped samples, no pronounced minimum has been found. Such abnormal behaviours are explained by the paralle l conduction from the quasi-bulk carriers and interface carriers. Thes e high-mobility InAs thin films are found to be suitable materials for making Hall elements. (C) 1998 Elsevier Science B.V. All rights reser ved.