scholarly journals Organoindium Precursor Purification by New Sorbents Based on Titanium and Zirconium Phosphates

1997 ◽  
Vol 15 (6) ◽  
pp. 429-435 ◽  
Author(s):  
Irina A. Grafova ◽  
Sergei A. Khainakov ◽  
Vladimir V. Strelko ◽  
Giovanni A. Battiston
Keyword(s):  
Zirconium Phosphate ◽  
Vapour Deposition ◽  
Aqueous Media ◽  
Chemical Vapour ◽  
Semiconductor Films ◽  
Zirconium Phosphates ◽  
Precursor Synthesis ◽  
Organometallic Precursors ◽  
The Stability ◽  
Deposition Techniques

High purity requirements for organometallic precursors have recently become critical in the field of III–V semiconductor films obtained by chemical vapour deposition techniques. Traditional purification routes employing physical methods need to be replaced by ones which are more rapid and effective. Such a route is described in this paper. This involves the elimination of any traces of impurity by applying several combinations of sorbents. In this way, complete elimination of lithium impurities introduced during precursor synthesis has been achieved by the use of titanium or zirconium phosphate sorbents (usually used as acidic ion exchangers in aqueous media). The method also preserves the stability of the organoindium precursor which is normally extremely sensitive to moisture. A possible explanation for these observations is given.

New Approach Towards The Deposition of I-III-VI Thin Films

2001 ◽  
Vol 692 ◽  
Author(s):  
Mohammad Afzaal ◽  
David Crouch ◽  
Paul O'Brien ◽  
Jin-Ho Park
Keyword(s):  
Thin Films ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
High Efficiency ◽  
Chemical Vapour ◽  
One Pot ◽  
Optimum Growth Temperature ◽  
Glass Substrates ◽  
Show Evidence ◽  
Organometallic Precursors

AbstractThe ternary chalcopyrite semiconductor Cu(In/Ga)(Se/S)2 is currently used as an absorber layer in high efficiency thin film solar cells. In this study, various types of I-III-VI (I = Cu, III = Ga or In, VI = S or Se) thin films (CuGaS2, CuInS2 and CuInSe2) were prepared from a series of organometallic precursors, M[(S/Se)2CNMeR]n (M = Cu, In, Ga; R = alkyl) by aerosol-assisted chemical vapour deposition (AACVD). In contrast to the metal alkyl compounds, MR3 (M = In and Ga; R = alkyl), which are pyrophoric, the precursors are easy to synthesize by one-pot reactions and are air stable. The optimum growth temperature for the preparation of these films on glass substrates using aerosol-assisted chemical vapour deposition (AACVD) was found to be above 400 °C in terms of crystallinity, although deposition does occur at lower temperatures. The films have been characterised using XRPD, SEM and EDS. SEM analyses show all films are microcrystalline. XRPD results show evidence of the crystalline nature of theses films. The results of this comprehensive study are presented and discussed.

Development of a SiNx-Based Barrier Coating for SiC Fibres

2015 ◽  
Vol 825-826 ◽  
pp. 256-263 ◽  
Author(s):  
Kristina Roder ◽  
Daisy Nestler ◽  
Daniel Wett ◽  
Bernd Mainzer ◽  
Martin Frieß ◽  
...  
Keyword(s):  
Coating Thickness ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Liquid Silicon ◽  
Barrier Coating ◽  
Fibre Coating ◽  
Variable Chemical ◽  
Pressure Chemical ◽  
Sic Composites ◽  
The Stability

Uncoated SiC fibres in SiC/SiC composites manufactured by the liquid-silicon infiltration (LSI) process show a strong degradation as a result of silicon attack. The goal of this research is the development of a SiNx-based fibre coating, which acts as a barrier against the liquid silicon. The coating is applied by means of low-pressure chemical vapour deposition (LPCVD) utilising the gaseous precursors silane (SiH4) and ammonia (NH3) on a commercial SiC multifilament yarn. The result is an amorphous fibre coating with an increasing coating thickness and a variable chemical composition from the middle of the yarn to the edges. The coated fibres exhibit a reduced characteristic Weibull strength in comparison to the uncoated fibres. In order to examine the stability of the films, the coated fibres undergo a heat treatment at 1450 °C in different environments (vacuum, argon and nitrogen). In all environments, the amorphous SiNxcoatings crystallise to the trigonal Si3N4. Depending on the coating thickness cracks and defects develop. However, the best results and the lowest amount of damaging occurs during the treatment in nitrogen.

scholarly journals Performance Analysis of GaN/AlGaN HEMTs Passivation using Inductively Coupled Plasma Chemical Vapour Deposition and Plasma Enhanced Chemical Vapour Deposition Techniques

2018 ◽  
Vol 68 (6) ◽  
pp. 572
Author(s):  
Sunil Kumar ◽  
Amit Malik ◽  
Dipendra Singh Rawal ◽  
Seema Vinayak ◽  
Hitendra Malik
Keyword(s):  
Chemical Vapour Deposition ◽  
Inductively Coupled Plasma ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Saturation Current ◽  
Gate Leakage Current ◽  
Inductively Coupled ◽  
Plasma Chemical Vapour Deposition ◽  
Gan Hemts ◽  
Deposition Techniques

<p class="p1">In the present paper SiN thin film has been studied as a passivation layer and its effect on AlGaN/GaN HEMTs is investigated using two different deposition techniques i.e PECVD and ICPCVD. AlGaN/GaN HEMTs devices passivated with optimised SiN film have delivered lower gate leakage current (from μA to nA). Device source drain saturation current (I<span class="s2">ds</span>) increased from 400mA/mm to ~550 A/mm and the peak extrinsic trans-conductance increased from 100 mS/mm to 170 mS/mm for a 0.8 μm HEMT device. The optimised SiN passivation process has resulted in reduced current collapse and increased breakdown voltage for HEMT devices.<span class="Apple-converted-space"> </span></p>

Radiation-Induced Defects in Electron and Proton Irradiated ZnS

1998 ◽  
Vol 540 ◽  
Author(s):  
S. Brunner ◽  
W. Puff ◽  
P. Mascher ◽  
A.G. Balogh
Keyword(s):  
Vapour Deposition ◽  
Proton Irradiation ◽  
Positron Lifetime ◽  
Chemical Vapour ◽  
Isochronal Annealing ◽  
Doppler Broadening ◽  
Defect Complexes ◽  
Radiation Induced ◽  
The Stability ◽  
Induced Defects

AbstractIn this contribution, we present a study aimed at investigating the microstructural changes of ZnS single crystals and CVD (chemical vapour deposition) grown crystals after electron and proton irradiation. Positron lifetime and Doppler-broadening measurements were performed to investigate the stability of the radiation induced defects and possible clustering mechanisms during isochronal annealing. After electron as well as proton irradiation the significant changes in the annihilation characteristics are indications of radiation induced open-volume-type defects. It is found that electron and proton irradiation causes different changes in the positron annihilation characteristics. After electron irradiation a significant defect component is observed which can be attributed to the annihilation in monovacancies. During isochronal annealing agglomerations to divacancy-type defects take place. Proton irradiation reveals a significantly different defect structure. Isochronal annealing causes agglomerations to larger defect complexes. The observed annealing stages are indications of the annealing of variously sized vacancy complexes.

Comparison of laser-ablation and hot-wall chemical vapour deposition techniques for nanowire fabrication

2006 ◽  
Vol 17 (11) ◽  
pp. S246-S252 ◽  
Author(s):  
E Stern ◽  
G Cheng ◽  
S Guthrie ◽  
D Turner-Evans ◽  
E Broomfield ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Deposition Techniques
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