Thickness and doping dependence of the optical gap in amorphous hydrogenated silicon films

Chacorn, V.; Haneman, D.

doi:10.1016/0038-1098(88)90348-1

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…4: E g does not change significantly with doping, in agreement with literature data, e.g. [16], which were obtained on thick (several 100 nm up to 2 lm) phosphorous-doped a-Si:H samples. It should be noted that a constant E g with doping is only found for intrinsic and n-type layers; for (thick) boron-doped a-Si:H layers, pronounced effects of doping on E g are reported and explained with variations in hydrogen content of these films (see references in [16]).…”

Section: Discussionsupporting

confidence: 89%

“…[16], which were obtained on thick (several 100 nm up to 2 lm) phosphorous-doped a-Si:H samples. It should be noted that a constant E g with doping is only found for intrinsic and n-type layers; for (thick) boron-doped a-Si:H layers, pronounced effects of doping on E g are reported and explained with variations in hydrogen content of these films (see references in [16]). For the Fermi level position, considerable differences are seen in comparison to thick films: Various authors (see e.g.…”

Section: Discussionmentioning

confidence: 99%

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Investigation of gap states in phosphorous-doped ultra-thin a-Si:H by near-UV photoelectron spectroscopy

Korte

Schmidt

2008

Journal of Non-Crystalline Solids

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Investigation of gap states in phosphorous-doped ultra-thin a-Si:H by near-UV photoelectron spectroscopy

Korte

Schmidt

2008

Journal of Non-Crystalline Solids

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“…They concluded that the Tauc optical gap associated with a-Si: H increases as the thickness of the film diminishes. Similar results have been found by Talukder et al, 3 Demichelis et al, 4,5 Chacorn and Haneman, 6 Nguyen et al, 7 and El-Naggar. 8 This increase in the Tauc optical gap associated with a-Si: H corresponding to decreased film thickness has been attributed to a number of factors.…”

Section: Introductionsupporting

confidence: 91%

The dependence of the Tauc and Cody optical gaps associated with hydrogenated amorphous silicon on the film thickness: αl Experimental limitations and the impact of curvature in the Tauc and Cody plots

Mok

O’Leary

2007

Journal of Applied Physics

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Using a model for the optical spectrum associated with hydrogenated amorphous silicon, explicitly taking into account fundamental experimental limitations encountered, we theoretically determine the dependence of the Tauc and Cody optical gaps associated with hydrogenated amorphous silicon on the thickness of the film. We compare these results with that obtained from experiment. We find that the curvature in the Tauc plot plays a significant role in influencing the determination of the Tauc optical gap associated with hydrogenated amorphous silicon, thus affirming an earlier hypothesis of Cody et al. We also find that the spectral dependence of the refractive index plays an important role in influencing the determination of the Cody optical gap. It is thus clear that care must be exercised when drawing conclusions from the dependence of the Tauc and Cody optical gaps associated with hydrogenated amorphous silicon on the thickness of the film.

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“…and when plotted in the Tauc co-ordinates (α⋅hν) 1/2 vs. (hν) [16] gives the value of the optical band gap Eg determined as the energy difference between the onsets of exponential tails of the allowed conduction bands [17]. Fig.2b represents the absorption spectra in the Tauc co-ordinates (α hν) 1/2 = A (hν -Eg).…”

Section: Resultsmentioning

confidence: 99%

Calculation of the optical constants of amorphous [(As2S3):(As2Se3)]1-x: Snx thin films

Iaseniuc¹

2012

SPIE Proceedings

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The modifications of optical parameters (optical band gap E g , absorption coefficient α, refractive index n) under light irradiation by He-Ne laser of the amorphous thin films with different amount of Sn were measured and calculated. In the present work the transmission spectra of bulk and thin films of [(As 2 S 3 ) 0.5 :(As 2 Se 3 ) 0.5 ] 1-x :Sn x (x=0; 1; 2 at.%) in the visible and middle infrared (IR) regions were studied. The red shift of the fundamental absorption edge under light exposure was observed, and the values of the optical band gap E g opt from the graphics in Tauc coordinates (α hν) 1/2 =A(hν -Eg) were obtained. The dispersion of the refractive index was examined. The relaxation of the relative optical transmission T/T 0 =f(t) under the light exposure (λ=633nm and λ=543nm) for amorphous [(As 2 S 3 ) 0.5 :(As 2 Se 3 ) 0.5 ] 1-x :Sn x thin films also was investigated. The relaxation curves of photodarkening under light irradiation were processing using the stretched exponential presentation of the data: (1-β) , where t is the exposure time, τ is the apparent time constant, A characterizes the exponent amplitude, t 0 and A 0 are the initial coordinates, and β is the dispersion parameter (0<β<1).

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Thickness and doping dependence of the optical gap in amorphous hydrogenated silicon films

Cited by 10 publications

References 16 publications

Investigation of gap states in phosphorous-doped ultra-thin a-Si:H by near-UV photoelectron spectroscopy

Investigation of gap states in phosphorous-doped ultra-thin a-Si:H by near-UV photoelectron spectroscopy

The dependence of the Tauc and Cody optical gaps associated with hydrogenated amorphous silicon on the film thickness: αl Experimental limitations and the impact of curvature in the Tauc and Cody plots

Calculation of the optical constants of amorphous [(As<sub>2</sub>S<sub>3</sub>):(As<sub>2</sub>Se<sub>3</sub>)]<sub>1-x</sub>: Sn<sub>x</sub> thin films

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