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The dependence of the Hall coefficient on magnetic field (B < 1.5 T), measured at 77 K, in short‐period (D < 40 nm), strained PbTe superlattices is analysed and interpreted. It is concluded that the superlattice is of type II. In addition to the electrons in PbTe and holes in SnTe, a third kind of charge carriers, having a high mobility, appears to take part in the conduction process. The third carriers can be both electron and hole‐like particles. Those carriers are connected with interface states which are expected to exist at the PbTe/SnTe interface. The carrier concentrations and mobilities in the bulk of the layers and at the interface are determined.

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The energy spectrum of a quantum dot made from IV-VI narrow gap semiconductors is studled. The calculations of the energy levels as functions of the dot radius are performed. When the anisotropy of the bare energy spectrum is strong, the energy levels are calculated using Fal'kovskii's adiabatic approximation for multiband systems. When the quantum dot material has an inverted band gap with respect to the host, the low-energy states within the fundamental gap are shown to arise.PACS numbers: 71.50.+t, 71.90.+qThe present day semiconductor technology is able to produce quantum dots which are effectively the objects of zero dimensionality [1][2][3]. The size quantization of the energy spectum in quantum dots takes place in all three dimensions. Here we study the energy spectrum of a quantum dot made of the narrow gap semiconductors and their solid solutions. The bulk crystal of this type has nonparabolic spectrum. The complexity of spectrum makes it nontrivial to solve the size quantization problem. In reality, the characteristic width L of the three-dimensional quantum well (i.e. the dot size) is not too small, L » α, where αn is the lattice constant. Thus, the envelope function approximation can be used. It implies that the basis wave functions contain as a set of multipliers the wave functions at the extremum pomt for only valence and conduction bands.We restrict ourselves to investigation of the type-I model of heterojunction, in which the relevant effective potential is Eg(r). The possible variation of other (797)