THE INFLUENCE OF CARBON AND BORON ATOMS ON THE OPTICAL AND ELECTRICAL PROPERTIES OF THIN FILM a-Si:H

2006 ◽  
Vol 20 (25) ◽  
pp. 1591-1596 ◽  
Author(s):  
ISIK KARABAY
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Window Layer ◽  
Optical And Electrical Properties ◽  
Research Plan ◽  
P Type ◽  
Gas Ratio ◽  
Made In

A series of undoped and p-doped a-SiC:H samples have been made in the framework of a research plan for obtaining high quality p-type window layers by "Plasma Enhanced Chemical Vapor Deposition (PECVD)" technique from the mixtures of silane ( SiH 4), methane ( CH 4) and diborane ( B 2 H 6) gases. For the optimization of the window layer, the dependence of the electrical (conductivity) and optical (band gap) properties due to altered ratios of methane and diborane gases were investigated. When the diborane gas ratio was changed from Y = 0.06 to Y = 0.24 with an increase of 0.06 steps at a constant of X = 0.948 methane gas ratio, the dark conductivity and optical band gap values changed from ~ 10-19 (Ω· cm )-1 to ~ 10-10 (Ω· cm )-1 and 2.542 eV to 2.178 eV, respectively, and between these values, the most appropriate layers can be selected.

Absorber Films of Antimony Chalcogenides via Chemical Deposition for Photovoltaic Application

2004 ◽  
Vol 836 ◽  
Author(s):  
M. T. S. Nair ◽  
Y. Rodríguez-Lazcano ◽  
Y. Peña ◽  
S. Messina ◽  
J. Campos ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Chemical Deposition ◽  
Dark Conductivity ◽  
Glass Substrates ◽  
Photovoltaic Application ◽  
Sodium Selenosulfate ◽  
P Type ◽  
Antimony Chalcogenides

ABSTRACTAntimony sulfide thin films (300 nm) have been deposited on glass substrates at 1–10°C from chemical bath. When heated these become crystalline and photoconductive with optical band gap (direct) of 1.7 eV. Thin films formed from chemical baths containing SbCl3 and sodium selenosulfate are of mixed phase Sb2O3/Sb2Se3, which when heated in the presence of Se-vapor converts to single phase Sb2Se3 film with optical band gap of 1.1 eV. Such films possess dark conductivity of 10-8 ohm-1cm-1 and show photosensitivity of two orders. Reaction of Sb2S3-CuS in nitrogen at 400°C produces crystalline, photoconductive p-type CuSbS2 with optical band gap (direct) of 1.5 eV. By controlling the deposition and heating condition, (i)Sb2S3-(p)CuSbS2 layer is formed, which is utilized in a photovoltaic structure, (n)CdS:In-(i)Sb2S3-(p)CuSbS2, with a Voc of 345 mV and Jsc 0.18 mA/cm2 under 1 kW m-2 tungsten halogen illumination. In the case of a structure, CdS:Cl-Sb2S3-Cu2-xSe, Voc of 350 mV and Jsc of 0.5 mA/cm2 are observed.

Highly Conductive and Wide Band GaP Microcrystalline Silicon Films Prepared by Photochemical Vapor Deposition and Applications to Devices

1985 ◽  
Vol 49 ◽  
Author(s):  
S. Nishida ◽  
H. Tasaki ◽  
M. Konagai ◽  
K. Takahashi
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Wide Band ◽  
Dark Conductivity ◽  
Hydrogen Gas ◽  
Microcrystalline Silicon ◽  
Wide Band Gap ◽  
Wide Gap ◽  
P Type ◽  
Photochemical Vapor Deposition

AbstractDoped hydrogenated microcrystalline silicon (μc-Si:H) and fluorinated hydrogenated microcrystalline (μc-Si:F:H) films were prepared by the mercury photosensitized decomposition of a disilane-hydrogen or a difluorosilane-hydrogen gas mixture, respectively. The maximum dark conductivity and optical band gap of μc-Si:H films were respectively 20 S•cm−1 and ∼2.0 eV for n-type and 1 S•cm−1 and 2.3 eV for p-type. A higher dark conductivity as much as 50 S•cm−1 and a wide gap of 2.0 eV were obtained for n-type μc-Si:F:H. It is most significant that the gaseous ratio of hydrogen to disilane should be enhanced to obtain such a highly conductive and wide gap film. The crystallinity of the photo-deposited μc-Si:H films appeared to be improved in comparison with that of films by the conventional plasma glow discharge technique.

Effect of B Boping Concentration on the Properties of P-Type Hydrogenated Amorphous Silicon Thin Films

2011 ◽  
Vol 239-242 ◽  
pp. 247-251
Author(s):  
Wei Yuan Wang ◽  
Qing Nan Zhao ◽  
Wen Hui Yuan ◽  
Pu Lei Yang ◽  
Hong Yu Liang ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Band Gap ◽  
Doping Concentration ◽  
Optical Band Gap ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Float Glass ◽  
B Doping ◽  
P Type ◽  
Hydrogenated Amorphous

P-type hydrogenated amorphous silicon films were deposited on float glass substrates by plasma enhanced chemical vapor deposition (PECVD). The effect of B doping concentration on the properties of the films was studied. The structure of the films was investigated by X-ray diffraction (XRD). The transmittance of the films was measured using an UV–Vis–NIR spectrophotometer in the wavelength range 200–2600nm.The film thickness was fitted by NKD-7000W optical thin film analysis system. The optical band gap of the films was obtained by the Tauc method. The conductivity of the films was tested by Electrometer Keithley 6517B. The results show that the optical band gap of the films changes from 1.93 eV to 1.65eV with the increase of B doping concentration, the highest conductivity of the film doped with 1.86% B2H6is 7.82 × 10-4S/cm.

Nanocrystalline Silicon Films with High Conductivity Prepared by Hot Wire Chemical Vapor Deposition

2012 ◽  
Vol 152-154 ◽  
pp. 513-518
Author(s):  
Chueh Yang Liu ◽  
Yao Ting Yun ◽  
Ping Chen Hsieh ◽  
Jen Ken Hsu ◽  
Shui Yang Lien
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Dark Conductivity ◽  
Hot Wire ◽  
P Type ◽  
Doping Ratio

Nanocrystalline silicon (nc-Si:H) grown by hot-wire chemical vapor deposition (HWCVD). We report on the effects of B2H6 doping ratio on the microstructural and optoelectrical properties of the p-type nc-Si:H thin films grown by HWCVD at low substrate temperature of 200 °C. An attempt has been made to elucidate the boron doping mechanism of the p-type nc-Si:H thin films deposited by HWCVD and the correlation between the B2H6 ratio, crystalline volume fraction, optical band gap and dark conductivity. Characterization of these films from Raman spectroscopy revealed that the high conductive film consists of mixed phase of nanocrystalline silicon embedded in an amorphous network. A small increase in B2H6 doping ratio showed marked effect on film microstructure. At the optimal condition, high dark conductivity (8 S/cm) with high optical band gap (~2.0 eV) was obtained.

AgSbSe2 thin films for photovoltaic structures produced through reaction of chemically deposited selenium thin films with Ag and Sb2S3

2004 ◽  
Vol 836 ◽  
Author(s):  
K. Bindu ◽  
M. T. S. Nair ◽  
P. K. Nair
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solid State ◽  
Band Gap ◽  
Solid State Reaction ◽  
Optical Band Gap ◽  
Dark Conductivity ◽  
Illumination Intensity ◽  
P Type ◽  
Ag Film

ABSTRACTSelenium thin films (350 nm) deposited from a 0.01 M solution of Na2SeSO3 of pH 4.5 maintained at 10 °C for 13 h, have been used as a source of selenium vapour for reaction with vacuum deposited Ag thin film on chemically deposited Sb2S3+Ag layers. When a stack of Sb2S3+Ag is heated in contact with Se film, AgSbSe2 is formed through solid state reaction of Sb2S3 and Ag2Se. The latter is formed at 80°C through the reaction of Ag-film in Se-vapour. This thin film is photoconductive and p-type. The optical band gap is nearly 1 eV and dark conductivity, 10-3 Ω-1cm-1. This thin film has been incorporated to form a photovoltaic structure, SnO2:F-(n)CdS:In-(i)Sb2S3-(p)AgSbSe2-silver print. Voc> 400 mV and Jsc>12 mA/cm2 have been observed in this under an illumination intensity of 1 kWm-2.

Material Properties of Sipos Films Prepared by XeCl Excimer Laser Annealing of a-Si:Nx Films

1996 ◽  
Vol 424 ◽  
Author(s):  
Hong-Seok Choi ◽  
Jae-Hong Jun ◽  
Keun-Ho Jang ◽  
Min-Koo Han
Keyword(s):  
Electrical Conductivity ◽  
Band Gap ◽  
Vapor Deposition ◽  
Material Properties ◽  
Laser Annealing ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Excimer Laser Annealing ◽  
Maximum Value

AbstractThe material properties of laser-annealed a-Si:Nx films were investigated. The a-Si:Nx films for laser-annealing were deposited by rf plasma enhanced chemical vapor deposition (PECVD) with NH3 and SiH4 gas mixtures. At the 0.35 of NH3/SiH4 ratio, the optical band-gap was abruptly increased to 2.82 eV from 2.05 eV by laser-annealing which indicates that Si-N bonding comes to be notable at that ratio. The electrical conductivity showed the maximum value of 4× 10-6 S/cm at the 0.11 of NH3/SiH4 ratio where the grain growth and the increase of Si-N bonding are optimized for the enhancement of electrical conductivity. The σP/σD ratio which is related to the defects states for photo generation centers was decreased with increasing NH 3/SiH 4 ratio. Our experimental data showed that the optical band gap and electrical conductivity of laserannealed a-Si:Nx films were dominantly affected by the NH3/SiH4 ratio at the 250 mJ/cm2 of laser-annealing energy density.

Light-Induced Effects on Fluorinated Amorphous and Microcrystalline Silicon Films

1996 ◽  
Vol 420 ◽  
Author(s):  
Hong-Seok Choi ◽  
Keun-Ho Jang ◽  
Jhun-Suk Yoo ◽  
Min-Koo Han
Keyword(s):  
Band Gap ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Silicon Film ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
Microcrystalline Silicon ◽  
Amorphous Silicon Film ◽  
Hydrogenated Amorphous

AbstractThe fluorinated amorphous and microcrystalline silicon (a,μc-Si:H;F) films have been prepared by rf plasma enhanced chemical vapor deposition (PECVD) with SiH 4 and SiF 4 gas mixtures. The stretching Si-O (1085 cm-1) and SiH2 (2100 cm-1) bands estimated from infrared (IR) spectroscope data have related to the evolution of crystallinity and the optical band gap was shifted by introducing Si-O bonds. The sub-band gap absorption coefficient in a,μc-Si:H;F films was about one order lower than that in hydrogenated amorphous silicon film (a-Si:H). The subband gap absorption in a-Si:H;F film was comparable to that in tic-Si:H;F films. The lightinduced degradation of a,μc-Si:H;F films were also suppressed.

Effect of MWCNT addition on the optical band gap of PVA/CS transient biocomposites

2021 ◽  
pp. 002199832110370
Author(s):  
Ömer Bahadır Mergen
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Band Gap ◽  
Optical Band Gap ◽  
Rapid Development ◽  
Measurement Techniques ◽  
Resistivity Measurement ◽  
Optical Parameters ◽  
Optical And Electrical Properties ◽  
Biocomposite Films

In recent years, as a result of increasing environmental concerns, biodegradable materials have gained great attention. With the rapid development of electronic technology, the importance of innovation and development of low-cost, sustainable, transient bioelectronics materials is increasing. In this research, the preparation of Poly(Vinyl Alcohol) (PVA), Chitosan (CS), and Multi-Walled Carbon nanotube (MWCNT) biocomposite films have been described. The solution mixing, ultrasonic mixing, and spin coating techniques were used to prepare the PVA/CS/MWCNT biocomposite thin films. UV–Vis absorption spectroscopy and two-point probe resistivity measurement techniques were used to study the optical and electrical properties of the biocomposite thin films. Optical band gap energies ( Eg) of PVA/CS/MWCNT biocomposites were obtained using the Tauc and Absorbance Spectrum Fitting (ASF) methods. Results obtained with both methods were found to be exactly the same. Experimental results have shown that with increasing MWCNT concentration, electrical conductivity (σ) increases from 1.75x10−16 S to 2.94x10−3 S, and Eg decreases significantly. At the same time, the fundamental optical parameters such as band tail (Urbach) energy ( Eu), refractive index ( n), absorption ( α), and extinction ( k) coefficient of the PVA/CS/MWCNT biocomposites were investigated in the UV-VIS range. The improvement observed in the optical and electrical properties of PVA/CS/MWCNT biocomposite films shows that these composites could be used as bioelectronics materials.

DEVELOPMENT OF HIGHLY CONDUCTIVE BORON-DOPED MICROCRYSTALLINE SILICON FILMS FOR APPLICATION IN SOLAR CELLS

2006 ◽  
Vol 20 (03) ◽  
pp. 303-314 ◽  
Author(s):  
QING-SONG LEI ◽  
ZHI-MENG WU ◽  
JIAN-PING XI ◽  
XIN-HUA GENG ◽  
YING ZHAO ◽  
...  
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Boron Doped ◽  
Deposition Processes ◽  
P Type

We have examined the deposition of highly conductive boron-doped microcrystalline silicon (μc- Si:H ) films for application in solar cells. Depositions were conducted in a very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) chamber. In the deposition processes, various substrate temperatures (TS) were applied. Highly conductive p-type microcrystalline silicon films were obtained at substrate temperature lower than 210°C. The factors that affect the conductivity of the films were investigated. Results suggest that the dark conductivity, which was determined by the Hall mobility and carrier concentration, is influenced by the structure. The properties of the films are strongly dependent on the substrate temperature. With TS increasing, the dark conductivity (σd) increases initially; reach the maximum values at certain TS and then decrease. Also, we applied the boron-doped μc- Si:H as p-layers to the solar cells. An efficiency of about 8.5% for a solar cell with μc- Si:H p-layer was obtained.

Effect of Various CF4/CH4 Flow Ratios on Structure and Optical Band Gap of Fluorinated Diamond-Like Carbon Thin Films

2010 ◽  
Vol 663-665 ◽  
pp. 312-315
Author(s):  
Jian Rong Xiao ◽  
Tao Tong ◽  
Yan Wei Li ◽  
Xin Hai Li
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Uniform Structure ◽  
Diamond Like Carbon ◽  
Radio Frequency Plasma ◽  
Frequency Plasma

Fluorinated diamond-like carbon (F-DLC) thin films are deposited using radio frequency plasma enhanced chemical vapor deposition under various gas flow ratios. The surface morphology of the F-DLC thin films deposited at lower gas flow ratios is a compact and uniform structure, and it became rough with the increase of gas flow ratios. The relative atomic contents of fluorine and chemical bonding configurations of C-Fx (x=1, 2, 3) in the thin films increases with the increase of gas flow ratios. The optical band gap of the thin films presents a decrease of different degree with the increase of gas flow ratios.

Sign in / Sign up

Export Citation Format

Share Document