Spin-dependent photoconductivity in undoped a-Si: H
47
Citation
12
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract Studies of spin-dependent photoconductivity in a-Si: H are reported. It is shown that, with increasing E.S.R. spin density, the photoconductivity decreases, but its spin dependence increases. The results demonstrate that dangling bonds are important trapping or recombination centres at room temperature. Prolonged exposure to above-gap illumination increases the spin dependence of photoconductivity and provides further evidence that light induces dangling bonds. The spin dependence of photoconductivity is compared with that of luminescence.Keywords:
Photoconductivity
Dangling bond
Studies of transient photoconductivity show that the primary effect of light soaking in hydrogenated amorphous silicon is to introduce dangling bonds of bulk density 1016–1017 cm−3. Light soaking reduces the μτ product of both electrons and holes to values which are quantitatively related to the observed increase in the dangling bond electron spin resonance (ESR) spin density. In addition, no change in the carrier drift mobilities is detected after light soaking.
Photoconductivity
Dangling bond
Transient (computer programming)
Electron Mobility
Cite
Citations (55)
Photoconductivity
Dangling bond
Time-of-Flight
Cite
Citations (20)
Cite
Citations (10)
Dangling bond
Carrier lifetime
Cite
Citations (0)
We have studied the stability of the luminescence from porous Si in the presence of a variety of ambient gases (e.g., N2, H2, forming gas, and O2). Although the optical properties are fairly stable under most conditions, illumination in the presence of O2 causes a substantial decrease in luminescence efficiency. Infrared measurements show that the surfaces of degraded samples are oxidized. The luminescence lifetime of the degraded material is found to be substantially reduced, and the density of Si dangling bonds increases by more than two orders of magnitude, which suggests that oxidation of the surface introduces nonradiative recombination channels. These observations indicate that the electronic properties at the surface of the porous Si play a key role in obtaining efficient luminescence from this material.
Dangling bond
Porous Silicon
Degradation
Cite
Citations (468)
The recombination processes in undoped hydrogenated amorphous silicon under steady-state illumination have been studied in order to explain the temperature dependences of photoconductivity. The recombinations of free carriers through the exponential tail states and through the Gaussian distributed dangling bond states were calculated in terms of the Shockley–Read theory and the occupation statistics of correlated defects. An additional recombination of trapped electrons and holes in the tail states through the dangling bonds by tunneling should be included in order to explain the experimental data of the activated photoconductivity at low temperatures.
Photoconductivity
Dangling bond
Cite
Citations (9)
A discussion of recombination and trapping kinetics is presented from the point of view of application to the analysis of transient photoconductive decay measurements in semiconductors. The transient solution is reviewed for the case of recombination in a single level, and the limiting approximations are presented for the case of n-type material. The role of minority carrier trapping in transient measurements is discussed, along with the effect of recombination in the trapping center. It is found that trapping effects can be treated as a special case in the recombination equations. Separation of the recombination and trapping effects in various temperature ranges is discussed.
Photoconductivity
Transient (computer programming)
Limiting
Carrier lifetime
Cite
Citations (38)
The transport and trapping of photocharges in liquid crystals placed between photoconductive polymer layers was investigated systematically. The transport of the photocharges is explained in terms of current paths that are formed along the bright sites of an interference pattern. Our study shows clearly that charge trapping occurs predominantly in the photoconductive poly(N-vinylcarbazole) layers and not in the insulating poly(vinyl alcohol) layers, contrary to a previous report.
Photoconductivity
Vinyl alcohol
Cite
Citations (28)
Abstract Photoluminescence and optically detected magnetic resonance measurements have been used to characterize the recombination processes in a-SiNx: H alloys. A quenching signal near g=2 is explained in terms of non-radiative recombination involving dangling bonds and two tail states, including a component at g=2.01, similar to that in a-Si, with a width which increases with nitrogen content. A broad enhancing signal at g=2 also resembles that seen in a-Si: H, with a width dependent on nitrogen content. Its origin is not yet clear. A signal at g=4 has been assigned to a triplet excitonic recombination process analogous to that proposed for a-SixC1−x: H. The importance of silicon dangling bonds in recombination confirms the predictions of the Robertson–Powell defect model.
Dangling bond
SIGNAL (programming language)
Cite
Citations (9)
Abstract Studies of spin-dependent photoconductivity in a-Si: H are reported. It is shown that, with increasing E.S.R. spin density, the photoconductivity decreases, but its spin dependence increases. The results demonstrate that dangling bonds are important trapping or recombination centres at room temperature. Prolonged exposure to above-gap illumination increases the spin dependence of photoconductivity and provides further evidence that light induces dangling bonds. The spin dependence of photoconductivity is compared with that of luminescence.
Photoconductivity
Dangling bond
Cite
Citations (47)