Electrical Conductivity and Structural Order of p-Type Amorphous Silicon Thin Films

2014 ◽  
Vol 1757 ◽  
Author(s):  
K. Shrestha ◽  
D. Whitfield ◽  
V. C. Lopes ◽  
A. J. Syllaios ◽  
C.L. Littler
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Raman Spectra ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Range Order ◽  
Total Conductivity ◽  
Hopping Conduction ◽  
Electrical Measurements ◽  
Hydrogen Incorporation

ABSTRACTThe dependence of dark conductivity and room temperature Raman spectra on boron and hydrogen incorporation in thin films of hydrogenated amorphous silicon (a-Si:H) prepared by plasma enhanced chemical vapor deposition was investigated. It was found that the dominant conductivity is Mott variable range hopping conduction. However, at lower temperatures, Efros-Shklosvkii hopping conduction is observed and contributes to the total conductivity. For structural characterization, transverse optical (TO) and transverse acoustic (TA) modes of the Raman spectra were studied to relate changes in short- and mid-range order to the effects of boron and hydrogen incorporation. With an increase of hydrogen incorporation and/or substrate temperature, both short and mid-range order improve, whereas the addition of boron results in the degradation of the short range order. The line width and frequency of the Raman TO Raman peak correlate with electrical measurements and suggest that this technique can be used for non-destructive characterization of a-Si:H.

Preparation and Spectrial Studies of Silicon Nitride Thin Films Containing Amorphous Silicon Quantum Dots

2021 ◽  
Vol 323 ◽  
pp. 48-55
Author(s):  
Jia Xin Sun ◽  
Bing Qing Zhou ◽  
Xin Gu
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Raman Spectra ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Blue Shift ◽  
Silicon Quantum Dots ◽  
Plasma Chemical Vapor Deposition

Silicon-rich silicon nitride thin films are prepared on P-type monocrystalline silicon wafer (100) and glass substrate by plasma chemical vapor deposition with reaction gas sources SiH4 and NH3. The deposited samples are thermally annealed from 600°C to 1000°C in an atmosphere furnace filled with high purity nitrogen. The annealing time is 60 minutes. Fourier transform infrared spectroscopy (FTIR) is carried out to investigate the bonding configurations in the films. The results show that the Si-H bond and N-H bond decrease with the increase of annealing temperature, and completely disappear at the annealing temperature of 900°C. But the Si-N bond is enhanced with the increase of annealing temperature, and the blue shift occurs, then Si content in the film increases. The Raman Spectra show that the amorphous Si Raman peak appears at 480 cm-1 in the film at 700°C. The Raman spectra of the films annealed at 1000 °C is fitted with two peaks, and a peak at 497 cm -1 is found, which indicated that the Si phase in the films changed from amorphous to crystalline with the increase of annealing temperature. The experiment also analyses the luminescence properties of the samples through PL spectrum, and it is found that there are five luminescence peaks in each sample under different annealing temperature. Based on the analysis of Raman spectrum and FTIR spectrum, the PL peak of amorphous silicon quantum dots appears at the wavelength range of 525-555nm, and the other four PL peaks are all from the defect state luminescence in the thin films, and the amorphous silicon quantum dot size is calculated according to the formula.

Effect of Ge Incorporation on Hydrogenated Amorphous Silicon Germanium Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition

2012 ◽  
Vol 569 ◽  
pp. 27-30
Author(s):  
Bao Jun Yan ◽  
Lei Zhao ◽  
Ben Ding Zhao ◽  
Jing Wei Chen ◽  
Hong Wei Diao ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon germanium thin films (a-SiGe:H) were prepared via plasma enhanced chemical vapor deposition (PECVD). By adjusting the flow rate of GeH4, a-SiGe:H thin films with narrow bandgap (Eg) were fabricated with high Ge incorporation. It was found that although narrow Eg was obtained, high Ge incorporation resulted in a great reduction of the thin film photosensitivity. This degradation was attributed to the increase of polysilane-(SiH2)n, which indicated a loose and disordered microstructure, in the films by systematically investigating the optical, optoelectronic and microstructure properties of the prepared a-SiGe:H thin films via transmission, photo/dark conductivity, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) measurements. Such investigation provided a helpful guide for further preparing narrow Eg a-SiGe:H materials with good optoelectronic properties.

scholarly journals Effect of the Nanoparticles on the Structure and Crystallization of Amorphous Silicon Thin Films Produced by rf Glow Discharge

1998 ◽  
Vol 13 (9) ◽  
pp. 2476-2479 ◽  
Author(s):  
E. Bertran ◽  
S. N. Sharma ◽  
G. Viera ◽  
J. Costa ◽  
P. St'ahel ◽  
...  
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Silicon Nanoparticles ◽  
Continuous Wave ◽  
Chemical Vapor ◽  
Hydrogen Gas ◽  
Electrical Measurements ◽  
Silicon Thin Films ◽  
Transmission Electron ◽  
Rf Glow Discharge

Thin films of nanostructured silicon (ns-Si:H) were deposited by plasma-enhanced chemical vapor deposition in the presence of silicon nanoparticles at 100 °C substrate temperature using a silane and hydrogen gas mixture under continuous wave (cw) plasma conditions. The nanostructure of the films has been demonstrated by diverse ways: transmission electron microscopy, Raman spectroscopy, and x-ray diffraction, which have shown the presence of ordered silicon clusters (1–2 nm) embedded in an amorphous silicon matrix. Because of the presence of these ordered domains, the films crystallize faster than standard hydrogenated amorphous silicon samples, as evidenced by electrical measurements during the thermal annealing.

Dual-Chamber Plasma Co-Deposition of Nanoparticles in Amorphous Silicon Thin Films

2006 ◽  
Vol 910 ◽  
Author(s):  
C. Anderson ◽  
C. Blackwell ◽  
J. Deneen ◽  
C. B. Carter ◽  
James Kakalios ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Plasma Reactor ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Dark Conductivity ◽  
Electrical Measurements ◽  
Capacitively Coupled ◽  
Silicon Thin Films ◽  
Si Nanoparticles ◽  
Flow Through

AbstractThe production of hydrogenated amorphous silicon films containing silicon nanocrystal-line inclusions (a/nc-Si:H) is demonstrated using a new deposition process. Crystalline Si nanoparticles around 5 nm in diameter are generated in a flow-through plasma reactor, and are introduced into a downstream capacitively-coupled plasma enhanced chemical vapor deposition reactor where the particles are “co-deposited” with the amorphous phase of the film. Transmis-sion electron microscopy confirms the presence of crystalline inclusions in these films, as well as providing confirmation that the crystalline particles are indeed produced in the flow-through re-actor and not in the capacitive plasma. Electrical measurements indicate an improvement in the dark conductivity of the intrinsic a/nc-Si:H films as the particle concentration is increased, sug-gesting that the particles have a doping effect on the films charge transport properties.

Influence of Hydrogen Dilution on Electrical Properties of Amorphous Silicon Thin Films Deposited on Glass Substrates

2011 ◽  
Vol 221 ◽  
pp. 117-122
Author(s):  
Ying Ge Li ◽  
Dong Xing Du
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Thin Layers ◽  
Glass Substrates ◽  
Silicon Thin Films ◽  
Hydrogen Dilution

Thin film Amorphous Silicon materials have found wide application in photovoltaic industry. In this paper, thin layers (around 300nm) of intrinsic hydrogenated amorphous silicon (a-Si:H) are fabricated on glass (Corning Eagle2000TM) substrates by employing plasma enhanced chemical vapor deposition (PECVD) system with gas sources of silane and hydrogen. The deposited thin films are proven to be material of amorphous silicon by Raman spectroscopy measurement and their electronic transport properties are thoroughly characterized in terms of photoconductivity, dark conductivity and photo response. The effect of Hydrogen dilution on electrical properties are investigated for a-Si:H thin films deposited in the temperatures range of 150~200°C. Results indicate that a-Si:H thin films on glass substrate owns device-quality electrical properties and could be applied on fabricating thin film solar cells as the absorber layer material and on other photovoltaic or photo electronic devices.

Amorphous Silicon Selenium Alloy Film Deposited Under Hydrogen Dilution

1991 ◽  
Vol 219 ◽  
Author(s):  
Muzhi He ◽  
Guang H. Lin ◽  
J. O'M. Bockris
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Selenium Concentration ◽  
Alloy Film ◽  
Dark Conductivity ◽  
Flow Rate Ratio ◽  
Selenium Atom ◽  
Alloy Films ◽  
Hydrogen Dilution ◽  
Photo Response

ABSTRACTAmorphous silicon selenium alloy films were prepared by plasma enhanced chemical vapor deposition with hydrogen dilution. The flow rate ratio of hydrogen to silane was about 8:1. Amorphous silicon selenium alloy was found to have an optical bandgap ranging from 1.7 eV to 2.0 eV depending on the selenium concentration in the films. The light to dark conductivity ratios of the alloy films are ∼ 104. The optical and electrical properties, Urbach tail energy and sub-bandgap photo response spectroscopy of the alloy film were investigated. The film quality of the alloy deposited with hydrogen dilution is greatly improved comparing to that of the alloy film deposited without hydrogen dilution. The electron spin resonance experiment shows that selenium atom is a good dangling bond terminator.

Effect of Nitrogen Doping on the Structure and Optical Properties of N-Type Hydrogenated Amorphous Silicon Thin Films

2011 ◽  
Vol 383-390 ◽  
pp. 6980-6985
Author(s):  
Mao Yang Wu ◽  
Wei Li ◽  
Jun Wei Fu ◽  
Yi Jiao Qiu ◽  
Ya Dong Jiang
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Amorphous Silicon ◽  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Silicon Thin Films ◽  
Frequency Plasma ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon (a-Si:H) thin films doped with both Phosphor and Nitrogen are deposited by ratio frequency plasma enhanced chemical vapor deposition (PECVD). The effect of gas flow rate of ammonia (FrNH3) on the composition, microstructure and optical properties of the films has been investigated by X-ray photoelectron spectroscopy, Raman spectroscopy and ellipsometric spectra, respectively. The results show that with the increase of FrNH3, Si-N bonds appear while the short-range order deteriorate in the films. Besides, the optical properties of N-doped n-type a-Si:H thin films can be easily controlled in a PECVD system.

The Effect of Plasma Power on the Properties of Amorphous Silicon-Germanium Thin Films

2011 ◽  
Vol 317-319 ◽  
pp. 341-344
Author(s):  
Long Gu ◽  
Hui Dong Yang ◽  
Bo Huang
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Silicon Germanium ◽  
Structural Characteristics ◽  
Chemical Vapor ◽  
Plasma Power ◽  
Glass Substrates ◽  
Frequency Plasma ◽  
Amorphous Silicon Germanium

Amorphous Silicon-germanium films were prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) on glass substrates. The structural characteristics, deposition rate, photosensitivity, and optical band gap of the silicon-germanium thin films were investigated with plasma power varying from 15W to 45W. The deposition rate increased within a certain range of plasma power. With the plasma power increasing, the photosensitivity of the thin films decreased. It is evident that varying the plasma power changes the deposition rate, photosensitivity, which was fundamentally crucial for the fabrication of a-Si/a-SiGe/a-SiGe stacked solar cells. For our deposition system, the most optimization value was 30-35W.

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