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.

Temperature-dependent reverse-bias current-voltage data obtained by Miller et al. [Appl. Phys. Lett. 84, 535 (2004)] for Schottky diodes fabricated on n-GaN are reinterpreted in terms of a phonon-assisted tunneling model. It is shown that the temperature dependence of the reverse-bias leakage current may be caused by the temperature dependence of the electron tunneling rate from traps in the metal-semiconductor interface to the conduction band of the semiconductor. A good fit of the experimental data with this theoretical model is obtained in the entire temperature range from 80to400K, when an effective mass of 0.222me and a phonon energy of 70meV are used for the calculation. The reverse current-voltage data for GaN diodes are also explained on the basis of this model.

No abstract

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.

The results of current–voltage (I–V) characteristics measured at different temperatures in polyethylene (PE) films obtained by our own experiments and the ones extracted from Suh K S et al (2000 J. Appl. Phys. 87 7333) are presented. The current depended strongly on temperature, namely, it increased with increase of temperature. The non-linearity in the I–V behaviour was observed at higher voltages. We suggest a phonon-assisted tunnelling model to explain the experimental results. The current mechanism in polymer diphenylaminostyrylbenzene (DASMB) films and in tris(8-hydroxyquinoline) aluminium (Alq3) films are also discussed.