Exponential band tails in polycrystalline semiconductor films

Werner, J. H.; Peisl, M.

doi:10.1103/physrevb.31.6881

Cited by 119 publications

(28 citation statements)

References 13 publications

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“…In poly-Si no influence of band-tail states to the ESR-signal could be found [1]. However, bandtail states do exist in poly-Si [3] but obviously the concentration of band-tail states is significantly lower than in Ac-Si:H. On the other hand, a large amount of db's is located at the grain boundaries [1,2]. For electron concentrations nN8Â10 18 cm À3 the db concentration decreases rapidly with increasing electron concentration [1].…”

Section: Discussionmentioning

confidence: 94%

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Electronic transport in P-doped laser-crystallized polycrystalline silicon

et al. 2005

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Section: Discussionmentioning

confidence: 94%

“…However, at the grain boundaries defects exists which where identified as silicon danglingbonds (db) [2]. Defects at grain boundaries are also the origin of potential barriers [3]. The electronic transport in polycrystalline silicon (poly-Si) is dominated by these potential barriers.…”

Section: Introductionmentioning

confidence: 99%

Electronic transport in P-doped laser-crystallized polycrystalline silicon

et al. 2005

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“…Exponential band tails, extending several 100 meV from the band edges into the gap were found for example in fine-grained polycrystalline silicon films 30,31,32 and were attributed to small wavelength potential fluctuations due to the spatial disorder. 33 In a-Si:H such states extend from the band edges into the gap over an energy range of 200 meV ͑conduction-band tail͒ or 300-400 meV ͑valence-band tail͒ ͑see, e.g., Ref.…”

Section: A Structure and Electronic Statesmentioning

confidence: 99%

Electron spin resonance investigation of electronic states in hydrogenated microcrystalline silicon

et al. 1999

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Phosphorus-doped microcrystalline silicon with high-crystalline volume fraction was prepared by very highfrequency plasma enhanced chemical vapor deposition. The material is studied by electron spin resonance and transport measurements as a function of doping and temperature. In all samples a resonance at gϭ1.998 is found with spin densities very similar to the phosphorus dopant density and also the carrier density at high doping levels. This resonance is related to doping-induced excess electrons. Its spin density is largely temperature independent, and the corresponding electrons occupy dopant or conduction band tail states at low temperatures, while they are excited into the conduction band at high T. This gradual transition is accompanied by changes in linewidth, g value and spin-lattice relaxation time. Hyperfine interaction with P nuclei is only observed for intermediate doping levels and has very small intensity. From the value of the hyperfine splitting, the effective Bohr radius of the impurity wave function is estimated to 12 Å. Transport at low temperatures (TϽ20 K) proceeds via hopping between donor states and/or conduction-band tail states. A thermal activation energy of 3.5 meV and similar localization lengths as from the hyperfine data are found for this process. At temperatures above 20 K electronic transport is governed by a wide distribution of activation energies.

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“…The existence of exponentially decaying band tails of electron states near the valence and conduction band of poly-Si has been demonstrated by admittance spectroscopy [65], temperaturedependent resistivity measurements [66], and optical absorption spectroscopy [53].…”

Section: Effect Of Hydrogenation On N-and P-doped Polycrystalline Silmentioning

confidence: 98%