Infrared absorption of hydrogenated amorphous SiC and GeC films

“…Indeed, a-SiC:H films are extensively studied both as typical materials of an amorphous system with variable disorder and microstrustures, [1][2][3] and for potential applications such as optoelectronic devices, 4) solar cells, 5) high temperature coatings 6) and X-ray masks. 7) The main reason for its success in device applications is that by incorporating hydrogen during plasma deposition, the paramagnetic dangling bonds are saturated, 8) which reduces the gap state density significantly and makes the n-and p-type doping possible.…”

Section: Introductionmentioning

confidence: 99%

Annealing Effect on the Optical Properties of a-SiC:H Films Deposited by PECVD

et al. 2002

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Effects of annealing temperature (T a ) on the structure of hydrogenated amorphous silicon carbide (a-SiC:H) films prepared by RF plasma chemical vapor deposition (CVD) method are investigated by using Fourier Transform-Infrared Spectrometry (FT-IR), X-ray Photoelectron Spectroscopy (XPS) and UV-VIS spectrophotometer techniques. It is found that an annealing process results in structural rearrangement and evacuation of hydrogen atoms from CH n and SiH n bonds. The emission of hydrogen bonded to silicon and carbon responsible for the decrease of optical band gap (E opt ) by 0.70 eV in the range of T a from 573 to 873 K. This hydrogen loss is interpreted in terms of hydrogen molecule formation and outerdiffusion. In addition, the surface morphology of films was investigated by atomic force microscopy (AFM).

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“…It was widely reported that decrease of the carbon content x in a-Si 1−x C x :H films in a broad range results in increase of the refractive index from 1.8…2.1 in carbonrich to 3.4…3.8 in silicon-rich species [24,[39][40]. This variation is obviously related with variation of relative contribution of C-C, Si-C and Si-Si bonds as well as nanoporosity of the structure.…”

Section: Resultsmentioning

confidence: 96%

“…2. The spectrum of as-deposited sample is composed by strong absorption bands at 780 cm -1 (Si-C stretching) and Table. The absorption band at 1010 cm -1 in a-Si 1-x C x :H films is commonly ascribed to rocking/waging vibration modes in CH 2 radicals bonded to silicon atoms -Si-CH 2 -Si [23][24][25][26][27]. But it is well known that the main absorption band in silicon sub-oxide SiO x (x < 2) is also located at 1000…1400 cm -1 depending on x [20].…”

Section: Resultsmentioning

confidence: 99%

Photoluminescent properties of oxidized stochiometric and carbon-rich amorphous Si1-xCx:H films

Vasin¹

2015

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. Near-stochiometric and carbon-rich a-Si 1−x C x :H thin films were deposited using the magnetron sputtering of Si target in Ar/CH 4 gas mixture. As-deposited nearstochimetric (x = 0.5) sample showed weak blue photoluminescence (PL), while PL of as-deposited carbon-rich (x = 0.7) sample was 20 times stronger and white in color. The films were annealed in pure argon, wet argon, and dry oxygen at 450 °C for 30 min. The intensity of PL in a-Si 1−x C x :H layers were enhanced by the factor from 2 to 12 after annealing in dependence on the annealing atmosphere. The strongest oxidation and strongest light emission were observed in carbon-rich series (x = 0.7) after annealing in oxidizing atmosphere. Structural properties of the films were characterized by infra-red absorption spectroscopy, ellipsometry and electron paramagnetic resonance. The effect of carbon enrichment of a-Si 1−x C x :H films and annealing atmosphere on the evolution of photoluminescence and local interatomic bonding structure in annealed material were studied and analyzed. It has been found that main effects of thermal treatments is strong enhancement of photoluminescence accompanied by formation of Si:C-H n and Si-O x C y bonding. The strongest oxidation effect as well as strongest photoluminescence were observed in carbon-rich a-SiC:H films.

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Infrared absorption of hydrogenated amorphous SiC and GeC films

Cited by 100 publications

References 9 publications

Physics of Amorphous Silicon–Carbon Alloys

Physics of Amorphous Silicon–Carbon Alloys

Annealing Effect on the Optical Properties of a-SiC:H Films Deposited by PECVD

Photoluminescent properties of oxidized stochiometric and carbon-rich amorphous Si1-xCx:H films

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