Very high mobility HgTe films grown on GaAs substrates by molecular-beam epitaxy

HgTe films have been grown in both the (100) and (111) orientations on (100) GaAs. In agreement with what has been reported for growth on II-VI substrates, we find higher Hall mobilities in (100) films. An 80-K mobility of 92 200 cm2 V−1 s−1 has been achieved. This is higher than has previously been reported for growth on (100) II-VI substrates. The conditions for growing these films are described.