The flash intensity of the ZnS-Cu phosphor induced by external dc field applied after excitation with ultraviolet light (Gudden-Pohl effect) is investigated. A method is used, which enables to study the temperature dependence of flash intensity for different applied voltages conditioned by centres of certain depth. The results are compared with the electron tunneling probability from the centre to the conduction band under phonon participation obtained in the paper. Mcmeaosanmb B C~~I U I K H nmMmiecueHmtr, nonysaeMbre n p~ HaaoweHm 3JIeKTpHW?CHOrO nOJlR Ha BO36ymReHHbIfi yJlbTpa@KOJleTOBbIM CBeTOM ZnS-CU JlIOMLIHO@Op (3(P@eHT fyJIIleHa-nOJIrl). npHMeHrlJIaCb MeTOABKa, nO3BOJIfiIOolqaJl E13JWklTb TeMlIepaTypHyIO 3aBACHMOCTb 3(P(PeKTa, 06yCJIOBJIeHHOrO UeHTpaMFi Pe3YJIbTaTbI CPaBHHBaH)TCfi C BePOrlTHOCTbH) T~KHeJIPSpOBaHHH 3JIeKTPOHOB C yW3CTMeM (POHOHOB 113 UeHTpa B 30HY IIPOBORRMOCTB , n0JIy~IeHHofi B HaCToRulefi onpeaenemoi4 rJIY6kiHb1, npFi p a 3 n~r~b 1 x HanpHmeHmx npmoHceHHoro IIOJIH.pa6ol.e.

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In this paper we would like to show the applicability of phonon-assisted tunnelling theories for explanation of temperature-dependent current–voltage (I–V) characteristics of diodes based on organic thin films of conjugated polymers, such as poly[2-methoxy, 5-(2′-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV). For this purpose the I–V characteristics measured for MEH-PPV by Campbell et al (1997 J. Appl. Phys. 82 6326), Lupton and Samuel (1999 J. Phys. D: Appl. Phys. 32 2973), and van Woudenbergh et al (2001 Appl. Phys. Lett. 79 1697) are compared with the free carrier generation rate dependence on field strength using the phonon-assisted tunnelling theories. A strong dependence of charge carrier mobility on temperature is also explained by this model. The presented model allows us not only to explain the temperature variation of I–V and mobility data, but also to estimate the density of traps taking part in the current flow.

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Abstract:We review and compare two models recently used to describe electronic transport in polymer fibers/nanotubes and carbon nanotubes including graphene nanoribbons, namely, variable range hopping (VRH) in different versions and their modifications on the one hand and electric-field-induced phononassisted tunneling (PhAT) on the other hand. The VRH model is mainly approved on behalf of the results of temperature dependences. However, the field dependencies of the conductivity in the framework of this model remain practically unexplained. At the same time, the PhAT model describes properly not only temperature dependence of conductivity measured in a wide temperature range, but also conductivity/current dependences on field strength using the same set of parameters characterizing the materials