Capture of carriers to screened charged centres and low temperature shallow impurity electric field break down in semiconductors

Free carrier capture by a screened Coulomb potential in semiconductors are considered. It is established that with decreasing screening radius the capture cross section decreases drastically, and it goes to zero when $$. On the basis of this result a new mechanism of shallow impurity electric field break down in semiconductors is suggested.Comment: 8 pages, latex, 1 figure in gif format, to be submitted to "Journal of Condensed Matter

Polaron Energy Spectrum in Quantum Dots

Energy spectrum of a weak coupling polaron is considered in a cylindrical quantum dot. An analytical expression for the polaron energy shift is obtained using a modified pertubation theory.Comment: 7 pages, IOP style LaTeX fil

A New Low-Noise Avalanche Photodiode With Micro-Pixel Structure

A new design of the avalanche photodiodes with an array of micro-pixel p-n-junctions was developed on base of metal-oxide-silicon structure. The thermal oxide layer of 1000A thickness contains tunnel oxide regions with about 25A thickness. The device exhibits a noise factor ~ 4 at a high multiplication factor (M~10000). A high space uniformity of sensitivity was found for gain of M~ 1000

Electronic properties and phase transitions in low-dimensional semiconductors

We present the first review of the current state of the literature on electronic properties and phase transitions in TlX and TlMX2 (M = Ga, In; X = Se, S, Te) compounds. These chalcogenides belong to a family of the low-dimensional semiconductors possessing chain or layered structure. They are of significant interest because of their highly anisotropic properties, semi- and photoconductivity, non-linear effects in their I-V characteristics (including a region of negative differential resistance), switching and memory effects, second harmonic optical generation, relaxor behavior and potential applications for optoelectronic devices. We review the crystal structure of TlX and TlMX2 compounds, their transport properties under ambient conditions, experimental and theoretical studies of the electronic structure, transport properties and semiconductor-metal phase transitions under high pressure, and sequences of temperature-induced structural phase transitions with intermediate incommensurate states. Electronic nature of the ferroelectric phase transitions in the above-mentioned compounds, as well as relaxor behavior, nanodomains and possible occurrence of quantum dots in doped and irradiated crystals is discussed.Comment: 70 pages, 38 figure