Прыжковая проводимость Мотта и Эфроса-Шкловского в пленках из наночастц Si, легированных фосфором и бором

The electrical characteristics of thin films formed from Si nanoparticles (nc-Si) with various degrees of doping are studied. To exclude the influence of ionic conductivity, the current parameters of the films were recorded in an ultrahigh vacuum (P ~ 3 – 5∙10–9 Torr) with preliminary high-temperature (9500C) annealing. An analysis of the temperature dependences of the conductivity showed that in nc-Si films formed from heavily doped nanoparticles (the concentration of free electrons ne is greater than 1019 cm-3), the transport is determined by variable-length hopping (VRH). In these samples, the Mott conductivity prevails at temperatures above 300C and at lower temperatures, the Efros-Shklovskii type variable range hopping conduction is dominate. In films with a medium level of doping of nanoparticles (ne <1019 cm-3), transport is realized by the Mott, Efros - Shklovskii and thermally activated conductivities. At the same time, thermally activated conductivity is dominated at temperatures above 560K. In nc-Si films formed from undoped nanoparticles, the transport parameters are determined by thermally activated conductivity and Mott's conductivity. Conductivity of Efros - Shklovskii is not observed in such films. From the analysis of the parameters corresponding to the Mott and Efros - Shklovsky conductivities, the localization lengths of wave functions, the density of states at the Fermi level (g (EF)), and average hopping lengths are found. The average hopping lengths in nc-Si films from nanoparticles pre-etched in HF are in the range 56 - 86 nm, which indicates that hopping in such films occurs via intermediate nanoparticles.

INFLUENCE OF THE X-RAY IRRADIATION ON A CRYSTALS β-TlInS2 POLITIPES CONDUCTIVITY

It was investigated the influence of temperature changes on conductivity of a non-irradiated and X- ray radiated samples of e-TlInS2 crystals polytypies. Object of the study - irradiated and radiated samples of e-TlInS2 crystals polytypes. Purpose of the study - experimental investigation conductivity temperature dependences on the DC (direct current) e-TlInS2 crystals irradiated and X-ray radiated С- and 2С- polytypes. Method of the study - the temperature dependence of electrical conductivity on DC was experimentally investigated in temperature range Т = 100-300 K for the non-irradiated and X-ray radiated C- and 2C-polytypes of e-TlInS2 crystals. It is shown that the basic mechanism of transfer of charge in the temperatures interval T=130-165 K for both e-TlInS2 crystals polytypies is variable range hopping conduction and such temperature intervals are wider in case of the radiated samples. The densities of localized states near the Fermi level were calculated, for both non-irradiated and X-ray radiatied (dose 2.7х103 Gy) samples of e-TlInS2 crystals polytypies. It was discovered that irradiation by the indicated dose of X-ray radiation of the samples both crystals e-TlInS2 polytypies increase of their conductivity, almost on an order, and also is accompanied by disappearance for non-irradiated sample of C-polytype unusual for semiconductors temperatures change of conductivity in the interval T=196-214 K. KEYWORDS: POLYTYPES, X-RAYS RADIATION, CONDUCTIVITY, SEMICONDUCTORS, HOPPING CONDUCTIVITY

Author Correction: Apparent Power Law Scaling of Variable Range Hopping Conduction in Carbonized Polymer Nanofibers

An amendment to this paper has been published and can be accessed via a link at the top of the paper.