Electronic Properties of Microcrystalline Silicon

1997 ◽  
Vol 467 ◽  
Author(s):  
R. Carius ◽  
F. Finger ◽  
U. Backhausen ◽  
M. Luysberg ◽  
P. Hapke ◽  
...  
Keyword(s):  
Vapour Deposition ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapour ◽  
Structural Defects ◽  
Photoluminescence Properties ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

ABSTRACTThe electronic and optical properties of microcrys tall ine silicon films prepared by plasma enhanced chemical vapour deposition are investigated with Hall-effect, electrical conductivity, photothermal deflection spectroscopy and photoluminescence measurements. In particular, the influence of the grain size and the crystalline volume fraction on the conductivity, the carrier density and the Hall mobility is investigated in highly doped films. A percolation model is proposed to describe the observed transport data. Photoluminescence properties were studied in un-doped films. It is proposed that the photoluminescence is due to recombination at structural defects similar to those observed in crystalline silicon.

Properties of Nano-crystalline Silicon-Carbide Films Prepared Using Modulated RF- PECVD

2009 ◽  
Vol 1153 ◽  
Author(s):  
Feng Zhu ◽  
Jian Hu ◽  
Ilvydas Matulionis ◽  
Augusto Kunrath ◽  
Arun Madan
Keyword(s):  
Silicon Carbide ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Dark Conductivity ◽  
Crystalline Volume Fraction ◽  
Photothermal Deflection Spectroscopy ◽  
Nano Crystalline ◽  
Dc Bias ◽  
Photothermal Deflection ◽  
Sic Films

AbstractWe report on the fabrication of nano-crystalline silicon-carbide (nc-SiC) using pulse modulated RF-PECVD technique, from silane (SiH4) and methane (CH4) gas mixtures which is highly diluted in hydrogen (H2). The microstructure of nc-SiC material is nanometer-size silicon crystallites embedded in amorphous silicon-carbide (a-SiC) matrix. As carbon incorporation in nc-Si film increases, the bandgap is enlarged from 1.1eV to 1.55eV as measured by Photothermal Deflection Spectroscopy (PDS) while the crystalline volume fraction decreases from 70% to about 20%. It is found that the crystalline volume fraction, grain size and dark conductivity of nc-SiC films can be enhanced with applying a negative DC bias to substrate during deposition.

Equilibration in Amorphous Silicon Nitride Alloys

1995 ◽  
Vol 377 ◽  
Author(s):  
Bruce Dunnett ◽  
Christopher H. Cooper ◽  
Darren T. Murley ◽  
Roderick A. G. Gibson ◽  
David I. Jones ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Growth Temperature ◽  
Vapour Deposition ◽  
Defect Density ◽  
Chemical Vapour ◽  
Amorphous Silicon Nitride ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Deposition Conditions

ABSTRACTSeveral series of amorphous silicon nitride thin films have been grown by plasma-enhanced chemical vapour deposition, where the ratio of ammonia and silane feed gases was held constant for each series while the deposition temperature was varied from 160 °C to 550 °C, and all other deposition conditions were held constant. Photothermal Deflection Spectroscopy measurements were used to determine the Urbach slope E0 and the defect density ND. It is found that ND is determined by E0 for most of these samples, suggesting that defect equilibration occurs in a-SiNx:H for x up to at least 0.6. The growth temperature at which the disorder is minimised increases to higher values with increasing x, which is explained in terms of a hydrogen-mediated bond equilibration reaction. Fourier Transform Infra Red spectroscopy measurements were performed to determine the changes in hydrogen bonding with growth temperature. The results suggest that a second bond equilibration reaction also occurs at the growing surface, but that equilibrium cannot be reached at higher temperatures because of hydrogen evolution from Si-H bonds.

Transport Path in Hydrogenated Microcrystalline Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
N. Wyrsch ◽  
C. Droz ◽  
L. Feitknecht ◽  
J. Spitznagel ◽  
A. Shah
Keyword(s):  
Raman Spectroscopy ◽  
Volume Fraction ◽  
Conductivity Measurement ◽  
Dark Conductivity ◽  
Transition Regime ◽  
Conductivity Data ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Crystalline Fraction ◽  
Transport Path

AbstractUndoped microcrystalline silicon samples deposited in the transition regime between amorphous and microcrystalline growth have been investigated by dark conductivity measurement and Raman spectroscopy. From the latter, a semi-quantitative crystalline volume fraction Xc of the sample was deduced and correlated with dark conductivity data in order to reveal possible percolation controlled transport. No threshold was observed around the critical crystalline fraction value Xc of 33%, as reported previously, but a threshold in conductivity data was found at Xc≈50%. This threshold is interpreted here speculatively as being the result of postoxidation, and not constituting an actual percolation threshold.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

Intrinsic and Doped m c-Si:H TFT Layers using 13.56 MHz PECVD at 250°C

2004 ◽  
Vol 808 ◽  
Author(s):  
Czang-Ho Lee ◽  
Denis Striakhilev ◽  
Arokia Nathan
Keyword(s):  
Performance Improvement ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Rf Power ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Low Threshold

ABSTRACTUndoped and n+ hydrogenated microcrystalline silicon (μc-Si:H) films for thin film transistors (TFTs) were deposited at a temperature of 250°C with 99 ∼ 99.6 % hydrogen dilution of silane by standard 13.56 MHz plasma enhanced chemical vapor deposition (PECVD). High crystallinity m c-Si:H films were achieved at 99.6 % hydrogen dilution and at low rf power. An undoped 80 nm thick m c-Si:H film showed a dark conductivity of the order of 10−7 S/cm, the photosensitivity of an order of 102, and a crystalline volume fraction of 80 %. However, a 60 nm thick n+ μc-Si:H film deposited using a seed layer showed a high dark conductivity of 35 S/cm and a crystalline volume fraction of 60 %. Using n+ μc-Si:H films as drain and source contact layers in a-Si:H TFTs provides substantial performance improvement over n+ a-Si:H contacts. Finally, fully μ c-Si:H TFTs incorporating intrinsic m c-Si:H films as channel layers and n+ μc-Si:H films as contact layers have been fabricated and characterized. These TFTs exhibit a low threshold voltage and a field effect mobility of 0.85 cm2/Vs, and are far more stable under gate bias stress than a-Si:H TFTs.

Thermal evaporation synthesis of SiC/SiOx nanochain heterojunctions and their photoluminescence properties

2014 ◽  
Vol 2 (37) ◽  
pp. 7761-7767 ◽  
Author(s):  
Haitao Liu ◽  
Zhaohui Huang ◽  
Juntong Huang ◽  
Minghao Fang ◽  
Yan-gai Liu ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Thermal Evaporation ◽  
Chemical Vapour ◽  
Deposition Method ◽  
Photoluminescence Properties ◽  
Catalyst Free ◽  
Chemical Vapour Deposition Method

Chainlike SiC/SiOx heterojunctions were prepared on a silicon wafer by a simplified catalyst-free thermal chemical vapour deposition method.

Electrical and Optical Properties of Oxygenated Microcrystalline Silicon (mc-Si:O:H)

1992 ◽  
Vol 242 ◽  
Author(s):  
M. Faraji ◽  
Sunil Gokhale ◽  
S. M. Chaudhari ◽  
M. G. Takwale ◽  
S. V. Ghaisas
Keyword(s):  
Optical Properties ◽  
Glow Discharge ◽  
Silicon Surface ◽  
Volume Fraction ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Electrical And Optical Properties ◽  
Radio Frequency Glow Discharge ◽  
Absorption Studies ◽  
Discharge Method

ABSTRACTHydrogenated microcrystalline silicon with oxygen(mc-Si:O:H) is grown using radio frequency glow discharge method. Oxygen is introduced during growth by varying it's partial pressure in the growth chamber. The crystalline volume fraction ‘f’ and the crystallite size ‘δ’ are found to vary with the oxygen content. Results indicate that oxygen can etch the silicon surface when present in low amount while it forms a-SiO2-x with increasing contents. Optical absorption studies in the range of 2 to 3 eV suggest that the absorption coefficient ‘α’ lies in between the values of c-Si and a-Si:H.being closer to a-Si:H. The Hall mobility measurements for these samples indicate that for optimum oxygen contents the mobility as high as 35 cm2 V-1 sec-1 can be obtained. Results on I-V characteristics for p-i-n structure are presented.

Photoluminescence in B-doped μc-Si:H

1992 ◽  
Vol 283 ◽  
Author(s):  
S. Q. Gu ◽  
J. M. Viner ◽  
P. C. Taylor ◽  
M. J. Williams ◽  
W. A. Turner ◽  
...  
Keyword(s):  
Broad Band ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Dark Conductivity ◽  
Microcrystalline Silicon ◽  
Band Tail ◽  
Pl Spectra ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Hydrogenated Amorphous

ABSTRACTPhotoluminescence (PL) has been investigated in hydrogenated microcrystalline silicon (μc-Si:H) samples as a function of boron doping for films prepared by remote plasma enhanced chemical vapor deposition. When the dark conductivity a is below about 10-5 S/cm, the PL spectra exhibit a shape which is close to that of the so-called band tail PL in undoped hydrogenated amorphous silicon (a-Si:H) at 77 K. When a increases, the PL intensity decreases at 77 K. For samples with a on the order of 10-3 S/cm, the PL spectra show only a narrow, low energy PL band which peaks around 0.8–0.9 eV. In these samples, the PL at higher energy is essentially not observable. This trend is similar to that which occurs in doped a-Si:H. However, for higher doping levels (σ ∼ 1 S/cm) the PL in μc-Si:H, although very weak, exhibits a broad band which contains intensity at higher energies. The absorption spectra in these samples, as measured by photothermal deflection spectroscopy (PDS), show the same relationships with the corresponding PL spectra as do the PDS spectra in doped a-Si:H.

scholarly journals In Situ Doping of Nitrogen in -Oriented Bulk 3C-SiC by Halide Laser Chemical Vapour Deposition

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 410
Author(s):  
Youfeng Lai ◽  
Lixue Xia ◽  
Qingfang Xu ◽  
Qizhong Li ◽  
Kai Liu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Chemical Vapour Deposition ◽  
High Speed ◽  
Vapour Deposition ◽  
Volume Fraction ◽  
Chemical Vapour ◽  
Optical Transmittance ◽  
Undoped Sample ◽  
Maximum Value

Doping of nitrogen is a promising approach to improve the electrical conductivity of 3C-SiC and allow its application in various fields. N-doped, <110>-oriented 3C-SiC bulks with different doping concentrations were prepared via halide laser chemical vapour deposition (HLCVD) using tetrachlorosilane (SiCl4) and methane (CH4) as precursors, along with nitrogen (N2) as a dopant. We investigated the effect of the volume fraction of nitrogen (ϕN2) on the preferred orientation, microstructure, electrical conductivity (σ), deposition rate (Rdep), and optical transmittance. The preference of 3C-SiC for the <110> orientation increased with increasing ϕN2. The σ value of the N-doped 3C-SiC bulk substrates first increased and then decreased with increasing ϕN2, reaching a maximum value of 7.4 × 102 S/m at ϕN2 = 20%. Rdep showed its highest value (3000 μm/h) for the undoped sample and decreased with increasing ϕN2, reaching 1437 μm/h at ϕN2 = 30%. The transmittance of the N-doped 3C-SiC bulks decreased with ϕN2 and showed a declining trend at wavelengths longer than 1000 nm. Compared with the previously prepared <111>-oriented N-doped 3C-SiC, the high-speed preparation of <110>-oriented N-doped 3C-SiC bulks further broadens its application field.

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