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Filters: Format: "application/pdf" Collection: "ir_uspace" Subject: "Amorphous silicon"
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CreatorTitleDescriptionSubjectDate
1 Vardeny, Zeev ValentineEffect of bias illumination on photoinduced absorption decay in ?-Si:HZeldov and Weiser1 proposed a model to explain the influence of optical biasing on the decay of photoinduced absorption (PA) in ?-Si:H at high temperatures observed by Pfost, Vardeny, and Tauc.2 This model differs from the model originally used2 for interpreting the experimental data at temperatures...Optical biasing; Bias illumination; Photoinduced absorption decay; a-Si:H; Amorphous silicon1985
2 Vardeny, Zeev ValentineHot-carrier thermalization in amorphous siliconThermalization of photoinduced carriers in a-Si and α-Si:H was studied with use of sub-picosecond-pump and probe techniques with parallel and perpendicular polarizations. The underlying process was identified as hot-carrier absorption whose cross section increases with the carrier excess energy. T...Amorphous silicon; Thermalization; Photoinduced carriers; Frohlich interaction1981-05
3 Vardeny, Zeev ValentineOptical bias control of dispersive relaxations in α-Si:HRelaxation of the photoinduced ir absorption band in α-Si:H was studied in the microsecond time domain as a function of cw bias illumination. The decays follow a power law t-α where the dispersion parameter a increases with bias illumination. At low temperatures, a increases linearly with the st...Optical bias control; Dispersive relaxations; a-Si:H; Amorphous silicon1984-01
4 Vardeny, Zeev ValentineOptical bias control of dispersive relaxations in α-SI:HRelaxation of the photoinduced ir absorption band in a-Si:H was studied in the microsecond time domain as a function of cw bias illumination. The decays follow a power law t-a where the dispersion parameter a increases with bias illumination. At low temperatures, a increases linearly with the stead...Optical bias; Dispersive relaxations; Amorphous silicon; a-Si:H; Photoinduced absorption; Bias-controlled tunneling; Multiple trapping1984-01
5 Vardeny, Zeev ValentineOptical modulation spectroscopy of a-Si:H based multilayer structuresSteady state optical modulation spectrum of a-Si:H/a-SiNx:H multilayer structure, its temperature dependence and time decay have been studied. For multilayers with very thin sublayers the onset of the spectrum is more gradual and occurs at higher energy than the spectrum for unlayered a-Si:H, indic...Optical modulation spectroscopy; a-Si:H; Amorphous silicon; Dangling bonds1986
6 Vardeny, Zeev ValentineOptical picosecond studies of carrier thermalization in amorphous siliconThermalization of photogenerated hot carriers in a-Si, a-Si:H and a-Si:H:F was studied using the pump and probe method with subpicosecond resolution. The process is optically observable because the absorption cross-section of the hot carriers depends on their excess energy. It was found that the en...Carrier thermalization; Amorphous silicon; Frohlich interaction1981
7 Vardeny, Zeev ValentineOptically detected magnetic resonance studies of undoped a-Si:HPhotogenerated carrier dynamics in undoped a-Si:H have been studied by photoinduced absorption (PA), photoluminescence (PL) and their respective optically detected magnetic resonances: PADMR and PLDMR. We have detected for the first time the "g = 4" resonance in PADMR in addition to the previously ...Undoped a-Si:H; Amorphous silicon; Carrier dynamics1996
8 Vardeny, Zeev ValentinePhotocarrier dynamics in compensated hydrogenated amorphous siliconThe photocarrier dynamics in compensated a-Si:H is studied using the time-dependent photomodulation technique in the subpicosecond-to-millisecond time range. We find that photocarriers are quickly trapped in shallow impurity levels for t < 10 psec, similar to the behavior in singly doped materials...Photocarriers; a-Si:H; Amorphous silicon; Fast trapping1986-03
9 Vardeny, Zeev ValentinePhotoinduced absorption spectra in amorphous Si:H and Ge:H and microcrystalline Si:HThe steady state subgap photoinduced absorpotion bands in a-Ge:H and a-Si:H are interpreted in terms of two kinds of optical transitions of photoexcited carriers from traps in the gap into the bands of which one produces absorption and the other produces bleaching. The photoinduced absorption in mic...Photoinduced absorption; Si:H; Ge:H; Amorphous silicon; Amorphous germanium; Microcrystalline silicon1984
10 Vardeny, Zeev ValentinePhotoinduced absorption spectra in α-GeH and α-Si:HMeasurements of steady-state photoinduced absorption in α-Ge:H and α-Si:H were extended to cover the energy range from 0.25 to 1.9 eV. The subgap photoinduced-absorption bands in both materials are interpreted in terms of four kinds of optical transitions of photogenerated carriers from traps in ...Photoinduced absorption; in a-GeH; a-Si:H; Amorphous germanium; Amorphous silicon1984-07
11 Vardeny, Zeev ValentinePicosecond optical time-of-flight studies of carrier transport in α-Si:H/α-SiNx:H multilayersWe report time-of-flight experiments in the time range from 0.2 psec to 1.8 nsec in 0-Si:H-a-SiNx:H multilayer structures using a purely optical technique. The transport mechanism of photoexcited carriers is shown to be dispersive and its characteristic parameters are determined in the temperature r...Time-of-flight; Amorphous silicon; Carrier transport; Photoexcited carriers1987-09
12 Vardeny, Zeev ValentinePicosecond photoinduced transmission associated with deep traps in phosphorous doped α-Si:HPhotoinduced transmission was observed in the picosecond time domain in phosphorusdoped a-Si:H and connected with deep hole traps produced by doping. The hole transport was found to be dispersive starting before 5 ps and temperature dependent. This shows that the energy distribution of shallow traps...Photoinduced transmission; Deep traps; Amorphous silicon; Phosphorous doped a-Si:H; Electronic relaxation response1982-04
13 Vardeny, Zeev ValentinePicosecond trapping of photocarriers in amorphous siliconTrapping of photoexcited carriers in the picosecond and subnanosecond time domains was studied by measuring the decay of photoinduced absorption (PA) in a-Si, a-Si:F, a-Si:H, and a-Si:H:F. We found that when the midgap density of states decreases, both the trapping time and its temperature dependenc...Photocarriers; Amorphous silicon; Picosecond trapping; Photoinduced absorption1983
14 Vardeny, Zeev ValentineSpin dependent photoinduced absorption in a-Si:HWe have studied photoexcitation dynamics in undoped a-Si:H from 80 K to 300 K by the techniques of photoluminescence (PL), photoinduced absorption (PA) and their respective versions of optically detected magnetic resonance, namely PLDMR and PADMR. Both PL and PA spectra are composed of low and high ...a-Si:H; Amorphous silicon; Spin dependent; Photoinduced absorption1997
15 Vardeny, Zeev ValentineStates in the gap of doped and undoped a-Si:H studied by the photomodulation spectroscopyThe steady state photomodulation spectrum, its temperature and excitation intensity dependences have been studied in phosphorous doped and undoped a-Si:H. The spectra are analyzed in terms of photocarriers trapped in band-tail states and dangling bonds (DB) defects in undoped samples and impurities ...Doped a-Si:H; Undoped a-Si:H; Amorphous silicon; Photomodulation spectroscopy; Mobility gap; Steady state photomodulation spectrum1987
16 Vardeny, Zeev ValentineSteady-state photomodulation spectroscopy of α-Si:H/α-SiNx:H multilayer structuresThe steady-state photomodulation (PM) spectrum and its temperature dependence were studied in α-Si:H/α-SiNx:H multilayer structures (MLS). We found that the photocarrier properties in MLS with Si sublayer thickness ds < 20 A are dominated by band-tail broadening resulting from increase in disorder...Steady-state photomodulation spectroscopy; Photocarrier properties; Amorphous silicon1987-05
17 Vardeny, Zeev ValentineStudies of picosecond carrier dynamics in polysilane alloys: evidence for geminate recombination in small hydrogenated amorphous silicon clustersThe ultrafast photocarrier dynamics in polysilane alloys amorphous (SiH2)n' has been studied using the picosecond photoinduced absorption (PA) technique. For excitation below the optical gap, the PA response decays exponentially and is faster at low temperatures. This is interpreted in terms of e-h ...Picosecond carrier dynamics; Polysilane alloys; Geminate recombination; a-Si:H; Amorphous silicon; Ultrafast relaxation; Photoexcited carriers1990
18 Vardeny, Zeev ValentineTransient-photomodulation-spectroscopy studies of carrier thermalization and recombination in α-Si:HThe transient response of mid-gap absorption in a-Si:H to pulsed optical excitation is studied as a function of time (300 ns to 30 ms) and sample temperature (10-220 K) with use of probe wavelengths ranging from 0.75 to 5.5 fim. A numerical inversion process applied to the data gives the distributio...Amorphous silicon; a-Si:H; Transient-photomodulation-spectroscopy; Carrier thermalization; Carrier recombination; Pulsed optical excitation1988-07
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