Photo and dark conductivity of doped amorphous silicon

Abstract

The photo and dark conductivity of boron-and phosphorus-doped amorphous silicon is measured in the temperature range from 100 to 400 K, for various doping levels. Increasing doping generally decreases the activation energy of dark conductirity, down to 0.2 eV, and also decreases the a,,-value (extrapolation of dark conductivity for T -00). This lowering of a , is explained by a temperature shift of the Fermi level plus a change in the conduction mechanism. The activation energy of photoconductivity is also lowered, a t least by phosphorus doping, which is understood by an influence of doping on the tailing of the bands.Die Dunkel-und Photoleitung von Bor-und Phosphor-dotiertem amorphem Silizium wird fur verschiedene Dotierungen zwischen 100 und 400 K gemessen. Bei wachsender Dotierung sinkt die Aktivierungsenergie der Dunkelleitfahigkeit bis herab zu 0,2 eV: der u,-Wert (die Extrapolation der Dunkelleitfiihigkeit fur T + 30) nimmt jedoch ebenfalls ab. Diese Abnahme wird durch Verschiebung des Ferminiveaus erkliirt, verbunden mit einer Anderung des Leitungsmechanismus. Die Aktivierungsenergie der Photoleitung wbd ebenfalls gesenkt, zumindest im Fall der PhosphorDotierung, was mit einer Bwinflussung der BandauslSufer durch die Dotierung erklart wird.

Doped hydrogenated nanocrystalline silicon oxide layers for high‐efficiency c‐Si heterojunction solar cells

“…Despite their limited thickness, a‐Si:H–based thin films induce significant parasitic losses when placed on the sunny side of the cell . Besides, E a of doped a‐Si:H layers is in the order of hundreds of meV because of their moderate doping efficiency . The attempt of reaching higher doping within a‐Si:H films increases defect density, which will deteriorate the effective carrier collection .…”

“…7 Besides, E a of doped a-Si:H layers is in the order of hundreds of meV because of their moderate doping efficiency. 8 The attempt of reaching higher doping within a-Si:H films increases defect density, which will deteriorate the effective carrier collection. 9 To quench this material bottleneck and owing to their superior electrical and favorable optical properties, hydrogenated nanocrystalline silicon (nc-Si:H) layers have been proposed for carrier-selective-contacts (CSCs) in SHJ solar cells.…”

The fallacy of Meyer-Neldel temperature as a measure of disorder

“…In 1977, the statistical shift model was introduced by Rehm and co-workers [4], whose basic idea was quite simple, but which has been developed with many complex variants and was widely adopted. The Fermi energy of a system will shift with temperature.…”

Investigation of the Meyer–Neldel compensation rule in binary selenium-based amorphous semiconductors

“…The most widely accepted one of these models, that is not associated with an entropy term, is the statistical shift model firstly proposed for the electronic properties of a-Si:H [40]. The basic idea of this model is simple; i.e., the Fermi energy level E F shifts with temperature.…”