SnTe-based films and superlattices (SLs) were prepared and their electrical properties were measured. A EuTe/SnTe SL exhibited a hole mobility of 2720 cm2/V s, which is the highest value reported for any semiconductor material at room temperature. The SnEuTe film also exhibited high hole mobility in contrast to the PbEuTe system. These properties are explained in terms of the band offsets of EuTe/SnTe heterojunction and a decrease in the number of Sn vacancies. In addition, SnTe/PbSe and SnTe/PbS SLs with thin SnTe layers displayed n-type conduction with Seebeck coefficients comparable to those for PbSe and PbS. These properties reflect the type II heterostructures.

The SnTe, Sn 1−x Eu x Te and Sn 1−x Sr x Te ͑x Ͻ 0.06͒ films were prepared by hot wall epitaxy. The ternary alloy films prepared in cation rich condition had hole concentration around 1 ϫ 10 19 cm −3 with high mobility exceeding 2000 cm 2 / V s at room temperature. Optical transmission spectra were also measured in the temperature range from 100 to 400 K and compared with theoretical calculations. Optical transmission spectra of the SnTe were simulated successfully assuming bumped band edge structures. A band inversion model was proposed for the Sn 1−x Eu x Te and Sn 1−x Sr x Te systems, and the optical transmission spectra were also simulated successfully assuming the band inversion model.

No abstract