The Effect of Deposition Procedure on the Conductivity of Hydrogenated Amorphous Silicon Multilayer Films.

1986 ◽  
Vol 70 ◽  
Author(s):  
G. Moddel ◽  
F.-C. Su ◽  
P. E. Vanier
Keyword(s):  
Defect Density ◽  
Multilayer Films ◽  
Oxide Interface ◽  
Hydrogenated Silicon ◽  
Plasma Enhanced Cvd ◽  
Amorphous Hydrogenated Silicon ◽  
Defective Layer ◽  
State Densities ◽  
Continuous Deposition ◽  
Hydrogenated Amorphous

ABSTRACTThe conductivity of multilayer P-doped amorphous hydrogenated silicon (a-Si:H) thin films is measured for films prepared with different, deposition procedures. Multilayer films are deposited by plasma enhanced CVD following a procedure in which the plasma is extinguished and the deposition chamber is filled with air or argon after the deposition of each layer. These films are compared to films grown in continuous deposition runs. The technique provides a direct means to determine the effects of continuous versus interrupted deposition and to analyze oxide interface and bulk gap state densities. Exposing the layers to air between depositions produces deleterious effects whereas the effect of argon exposure are slight. Literature values for the density of states in oxidized a-Si:H are used to provide evidence for a defective layer in very thin P-doped a-Si:H having a defect density of over 1013 cm−2 eV−1 approximately 0.3 eV below the transport level.

Light-induced Stability of Layered Amorphous Hydrogenated Silicon Grown with Alternating Substrate Temperature

1996 ◽  
Vol 420 ◽  
Author(s):  
Jong-Hwan Yoona ◽  
Czang-Ho Lee
Keyword(s):  
Substrate Temperature ◽  
Defect Density ◽  
Single Layer ◽  
Light Illumination ◽  
Hydrogenated Silicon ◽  
Layer Film ◽  
Amorphous Hydrogenated Silicon ◽  
Improved Stability ◽  
Single Layer Film ◽  
Hydrogenated Amorphous

AbstractWe present the results of studies on the light-induced stability of undoped layered hydrogenated amorphous silicon films grown with alternating substrate temperature between optimal and non optimal temperatures for device-quality films. Compared to the single layer films grown at optimal substrate temperature, the layered films show improved stability in the lightinduced state. Under intense light illumination of 3 W/cm2, the steady-state defect density of the layered film reached a saturation of 2×1016 cm−3, while the single layer film saturates at about 6×1016 cm−3. It is found that in the completely degraded state the photoconductivity in the layered film is also improved by a factor of two compared to the single layer film.

PREPARATION AND CHARACTERIZATION OF GRADED BANDGAP AMORPHOUS HYDROGENATED SILICON-SULFUR THIN FILMS

1992 ◽  
Vol 06 (08) ◽  
pp. 469-475
Author(s):  
M. HAMMAM
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Graded Layers ◽  
Rf Glow Discharge ◽  
Optical Bandgaps ◽  
Silicon Based ◽  
Hydrogenated Amorphous ◽  
Graded Bandgap

Compositionally graded hydrogenated amorphous silicon-sulfur alloys ( a-Si 1−x S x: H ) were grown by RF glow discharge decomposition of silane and hydrogen sulfide gases. Infrared spectra show clear evidence for the incorporation of sulfur in the form of Si-S bonds in the material. The graded bandgap films possess optical bandgaps ranging from 1.91 to 2.05 eV depending on the RF power. The compositionally graded layers display high photosensitivities indicating that they may be ideal candidates for use in amorphous silicon based tandem cells.

Efficient Visible Room Temperature Photoluminescence in Wide Gap Hydrogenated Amorphous Silicon-Carbon Alloys

1994 ◽  
Vol 336 ◽  
Author(s):  
Leandro R. Tessler ◽  
Ionel Solomon
Keyword(s):  
Room Temperature ◽  
Urbach Energy ◽  
Photoluminescence Intensity ◽  
Tetrahedral Coordination ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Silicon Carbon ◽  
Hydrogenated Amorphous ◽  
Carbon Concentrations ◽  
Phonon Model

ABSTRACTWe report a photoluminescence study on amorphous hydrogenated silicon carbon (a-Si1-xCx:H) alloys with carbon concentration in the range O < x < 0.5, prepared by PECVD in the “low-power” regime, that preserves the tetrahedral coordination of the carbon atoms. These samples have optical gaps higher than conventional “high power” alloys with the same carbon content. For carbon concentrations below x = 0.2 the photoluminescence behaves essentially as in pure a-Si:H with increased gap, Urbach energy and DOS. For higher carbon concentrations there is a change in the recombination process, that we attribute to a change in the dominating diffusion process of the photogenerated carriers. The integrated photoluminescence intensity for carbon-rich samples is very weakly dependent on the temperature, and at room temperature it approaches that of pure a-Si:H at 77K. For all samples, the photoluminescence bandwidth can be well described by a zero-phonon model.

Low defect density amorphous hydrogenated silicon prepared by homogeneous chemical vapor deposition

1982 ◽  
Vol 40 (11) ◽  
pp. 973-975 ◽  
Author(s):  
B. A. Scott ◽  
J. A. Reimer ◽  
R. M. Plecenik ◽  
E. E. Simonyi ◽  
W. Reuter
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Defect Density ◽  
Chemical Vapor ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Homogeneous Chemical

Room Temperature Light Induced Electron Spin Resonauce In Undoped Hydrogenated Amorphous Silicon (a-Si:H)

1986 ◽  
Vol 70 ◽  
Author(s):  
R. Pandya ◽  
S. Zafar ◽  
E. A. Schiff
Keyword(s):  
Electron Spin ◽  
Room Temperature ◽  
Small Shift ◽  
Hydrogenated Silicon ◽  
Transient Photocurrent ◽  
Amorphous Hydrogenated Silicon ◽  
Spin Resonance ◽  
Absorption Studies ◽  
G Value ◽  
Hydrogenated Amorphous

ABSTRACTThe effects of illumination upon the absorption electron spin resonance spectrum of the dangling bond defect system have been studied in undoped amorphous hydrogenated silicon (a-Si:H). A small shift of the inhomogeneous envelope of the system towards higher g-value is observed at roomtemperature. The shift is not accompanied by a significant change in the signal. Results are reported which indicate that this shift is not due to illumination induced heating of the specimen or calibration changes of the spectrometer. The results may be related to previously reported optical bias effects upon transient photocurrent and photoinduced absorption studies.

Photocorrosion of hydrogenated amorphous silicon: effect of the solvent

1989 ◽  
Vol 67 (10) ◽  
pp. 980-983
Author(s):  
O. Savadogo ◽  
A. Yelon
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Ac Impedance ◽  
Corrosion Process ◽  
Oxide Growth ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Hydrogenated Amorphous

The photocorrosion of amorphous hydrogenated silicon (a-Si:H) in different solvents was studied. Impedance measurements were performed under potentiostatic conditions. At each potential, the impedance Z(ω, V) was determined in the frequency range 5 Hz–100 kHz. The Z(ω, V) diagrams were analyzed and the corrosion sensitivity of the material in different electrolytes was determined. A correlation between electroactivity domain and ac impedance curves is proposed. A relationship is used to describe the anodic corrosion process in different solvents. The electrolyte that shows no oxide growth at the semiconductor – electrolyte interface was deduced.

Correlation Between Minority Carrier Diffusion Length and Microstructure in a-Si:H Thin Films

1993 ◽  
Vol 297 ◽  
Author(s):  
G. Conte ◽  
G. Fameli ◽  
A. Rubino ◽  
E. Terzini ◽  
F. Villani ◽  
...  
Keyword(s):  
Steady State ◽  
Carrier Transport ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Defect Density ◽  
Hydrogen Distribution ◽  
Steady State Condition ◽  
Hydrogenated Silicon ◽  
Morphological Variations ◽  
Amorphous Hydrogenated Silicon

Aim of this work is to investigate the opto-electronic properties of amorphous hydrogenated silicon (a-Si:H). The deposition temperature nas been used as a driving force to modify the morphology and bonded hydrogen distribution. The influence of the hydrogen microstructure on the carriers μτ product has been examined. The majority and minority carrier μτ have been evaluated from the diffusion length measurement, by using the Steady State Photocarrier Grating (SSPG) technique, and from the photoconductivity in the steady state condition (SSPC). The μτ values have been correlated with the defect density and the Fermi level position. Some considerations are proposed to explain the carrier transport in terms of the compositional inhomogeneities in Si:H alloys due to the morphological variations.

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