Amar Merazga - Academia.edu (original) (raw)
Uploads
Papers by Amar Merazga
In this paper, we report on the simulation of steady state photoconductivity in un-doped a- Si:H ... more In this paper, we report on the simulation of steady state photoconductivity in un-doped a- Si:H at temperatures from 30 to 500 K. The model is based on recombination at dangling bond states and band tail states. It takes also into account the hopping transitions in the conduction hand tail states to describe the conduction in localized states at low temperatures. At high temperatures, the multiple trapping process is considered to describe the conduction in extended states. The density of states includes the exponential density of conduction band tail states and valence band tail slates and the density of dangling bond states. This later is determined by the Defect Pool Model 'DPM'. The experimental features observed on the temperature dependence of the photoconductivity ( p σ ) are generally the thermal quenching, the low activated region and the temperature independent photoconductivity at very low temperatures. All these observations are well reproduced by the model in...
Journal of Physics: Condensed Matter, 2006
Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon over... more Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon over a wide temperature range (25-500 K) is extended, to include previously neglected carrier transitions between localized states. In addition to free carrier capture (emission) transitions into (from) localized states, we include the process of electron hopping in conduction band tail states. Exponential distributions are assumed for both conduction and valence band tail states, while the dangling bond defect distribution is calculated in accordance with the defect pool model. Localized to extended state transitions follow the Simmons and Taylor statistics, and localized to localized state transitions involve electron hopping between nearest neighbour sites. Comparison with simulations in the absence of electron hopping reveals a smooth transition around 110 K, between regions of (high temperature) extended state conduction and (low temperature) hopping conduction. A hopping transport energy level is identified as the peak of the energy distribution of the hopping photocarriers, and shows a temperature dependence in agreement with existing theoretical work.
In this paper, we report on the simulation of steady state photoconductivity in un-doped a- Si:H ... more In this paper, we report on the simulation of steady state photoconductivity in un-doped a- Si:H at temperatures from 30 to 500 K. The model is based on recombination at dangling bond states and band tail states. It takes also into account the hopping transitions in the conduction hand tail states to describe the conduction in localized states at low temperatures. At high temperatures, the multiple trapping process is considered to describe the conduction in extended states. The density of states includes the exponential density of conduction band tail states and valence band tail slates and the density of dangling bond states. This later is determined by the Defect Pool Model 'DPM'. The experimental features observed on the temperature dependence of the photoconductivity ( p σ ) are generally the thermal quenching, the low activated region and the temperature independent photoconductivity at very low temperatures. All these observations are well reproduced by the model in...
Journal of Physics: Condensed Matter, 2006
Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon over... more Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon over a wide temperature range (25-500 K) is extended, to include previously neglected carrier transitions between localized states. In addition to free carrier capture (emission) transitions into (from) localized states, we include the process of electron hopping in conduction band tail states. Exponential distributions are assumed for both conduction and valence band tail states, while the dangling bond defect distribution is calculated in accordance with the defect pool model. Localized to extended state transitions follow the Simmons and Taylor statistics, and localized to localized state transitions involve electron hopping between nearest neighbour sites. Comparison with simulations in the absence of electron hopping reveals a smooth transition around 110 K, between regions of (high temperature) extended state conduction and (low temperature) hopping conduction. A hopping transport energy level is identified as the peak of the energy distribution of the hopping photocarriers, and shows a temperature dependence in agreement with existing theoretical work.