The temperature dependence of the photoconductivity of n-type a-Si:H and the effect of staebler-wronski defects

Vomvas, A.; Fritzsche, H.

doi:10.1016/0022-3093(87)90197-9

Cited by 28 publications

(8 citation statements)

References 5 publications

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“…The results indicated that the MPC of a-HgCdTe thin films show an activated behavior in the range of 80K-300K. The MPC I p (proportional to photoconductivity σ p , I p ∝σ p ) produced by the thermal activation of photogenerated carrier, follows the exponential relation [8][9] :…”

Section: Methodsmentioning

confidence: 96%

The modulated photocurrent of amorphous HgCdTe thin films

et al. 2011

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Amorphous HgCdTe thin films were deposited on quartz substrate by RF magnetron sputtering technique. The modulated photocurrent(MPC) of amorphous HgCdTe thin films has been investigated as a function of temperature T, the excitation light intensity F, and applied electric fields E B . The results indicated that the modulated photocurrent show an activated behavior in the range of 80K-300K. The activated energy ΔE ap of the modulated photocurrent was found to strongly depend on temperature, whereas it is nearly independent of the applied electric field. The exponent γ in the power law relationship (I p ∝F γ ) between excitation light intensity F and modulated photocurrent of amorphous HgCdTe thin films was obtained at different temperature. The γ depends strongly on the temperature T, but it is independence of applied electric fields E B . The values of exponent γ of amorphous HgCdTe thin films lie between 0.5 and 1.0. The results indicated a continuous distribution of localized states exists in amorphous HgCdTe thin films.

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Section: Methodsmentioning

confidence: 96%

The modulated photocurrent of amorphous HgCdTe thin films

et al. 2011

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“…(3) can be neglected, then (4) This is the fundamental condition required for the resulting value of r to lie between 0.50 and 1.0. Since n=G/[VnSnCNR -n R )), (5) where G is the excitation rate, Un is the electron thermal velocity, and SrI is the electron-capture cross section of the unoccupied recombination centers, combination of Eqs.…”

Section: Single Recombination Center Model With An Exponential Trap Dmentioning

confidence: 99%

Variation of photoconductivity with doping and optical degradation in hydrogenated amorphous silicon

Bube

Redfield

1989

Journal of Applied Physics

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A simple model for photoconductivity in a-Si:H is shown to be capable of describing the variations of photoconductivity observed both with doping and with optical degradation. The model consists of a trivalent recombination center with consideration only of transitions connecting the centers and extended states, and of exponential conduction and valence-edge tail states with occupancy described simply by the locations of the dark or quasi-Fermi levels. The model describes the changes in the magnitude of photoconductivity with doping or optical degradation as arising primarily from changes in the density of effective recombination centers caused by shifts in the location of the dark Fermi level, and only secondarily from changes in the total density of dangling bonds. The model also describes the change in the exponent for the variation of photoconductivity as a power of the excitation rate; this exponent changes from a value of 0.50, when the density of electrons trapped in conduction tail states is proportional to the density of neutral recombination centers, to a value of 1.0 when an appreciable density of neutral recombination centers exists in thermal equilibrium. Both qualitative and semiquantitative agreement are demonstrated between the predictions of the model and published experimental data on doping and optical degradation.

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“…Typical measurements of steady state photoconductivity (SSPC) in hydrogenated amorphous silicon (a-Si:H) as a function of temperature and doping are shown in figure 1 [1], covering a wide temperature range and showing all the SSPC features [1,2]. In the undoped case, for instance, four regions can be distinguished: region (I) at very low temperatures (T < 50 K), where the SSPC is independent of temperature, region (II) at intermediate temperatures (50 K < T < 150 K), where the SSPC rises with increasing temperature by several orders of Temperature dependence of the normalized SSPC (σ ph /eG) in logarithmic scale for undoped, p-type and n-type a-Si:H. The dopant concentration in the plasma gas is indicated.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon including localized state electron hopping

Merazga¹,

Tobbeche²,

Main³

et al. 2006

J. Phys.: Condens. Matter

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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.

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The temperature dependence of the photoconductivity of n-type a-Si:H and the effect of staebler-wronski defects

Cited by 28 publications

References 5 publications

The modulated photocurrent of amorphous HgCdTe thin films

The modulated photocurrent of amorphous HgCdTe thin films

Variation of photoconductivity with doping and optical degradation in hydrogenated amorphous silicon

Numerical simulation of the steady state photoconductivity in hydrogenated amorphous silicon including localized state electron hopping

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