Inert Gas Dilution and Ion Bombardment Effects in Room Temperature (35°C) Plasma Deposition of a-Si:H

1996 ◽  
Vol 420 ◽  
Author(s):  
Easwar Srinivasan ◽  
Daniel A. Lloyd ◽  
Ming Fang ◽  
Gregory N. Parsons

AbstractPlasma enhanced chemical vapor deposition (PECVD) of a-Si:H with silane or silane and hydrogen at temperatures lower than 200°C commonly results in films with significant dihydride bonding and a high defect density. In this paper, we demonstrate the formation of monohydride dominant a-Si:H films using rf parallel plate PECVD at 35°C at deposition rates greater than 100 Å/min. In the as-deposited state, these films have low dark conductivity (∼10−9 S/cm) and low photoconductivity. Annealing the films at 150°C caused the monohydride dominant films to show photo to dark conductivity ratio near 105. Our results also indicate that an increase in monohydride fraction is not linked with a decrease in deposition rate.

2004 ◽  
Vol 832 ◽  
Author(s):  
Eun-Kyu Lee ◽  
Boris V. Kamenev ◽  
Pavel A. Forsh ◽  
Ted I. Kamins ◽  
Leonid Tsybeskov

ABSTRACTSamples of Ge Nanowires (Ge NWs) grown by chemical vapor deposition (CVD) on single crystal, (100) and (111) oriented Si substrates were studied with respect to their electrical properties. Using different contact geometries, direct current (DC) and alternating current (AC) electrical and photoelectrical measurements were carried out at room temperature. A rectifying junction behavior was observed indicating a low defect density at NWs/substrate heterointerface. AC conductance exhibits significant frequency dependence with a power law behavior, suggesting that carrier transport in Ge NW volume is associated with hopping processes.


1998 ◽  
Vol 507 ◽  
Author(s):  
K. Pangal ◽  
J.C. Sturm ◽  
S. Wagner

ABSTRACTThe crystallization of amorphous silicon (a-Si:H) deposited by plasma enhanced chemical vapor deposition (PECVD) by thermal annealing is of great interest for display and silicon-on-insulator (SOI) technologies, though long anneal times (about 20 hrs) at 600 °C are typically required. We report that a room temperature hydrogen plasma exposure in a parallel plate diode type Reactive Ion Etcher (RIE) can reduce this crystallization time by a factor of five. This plasma enhanced crystallization can be spatially controlled by masking with patterned oxide, so that both amorphous and polycrystalline areas can be realized simultaneously at desired locations. This effect is due to the creation of seed nuclei at the surface, which enhance crystallization rates.


1991 ◽  
Vol 219 ◽  
Author(s):  
M. J. Williams ◽  
C. Wang ◽  
G. Lucovsky

ABSTRACTUndoped films of μc-Si deposited by RPECVD are n-type with a room temperature dark conductivity of ∼6×10-4 S/cm and an activation energy of ∼0.3 eV. This is due to native donor-like defects. We report on the conductivity and photoconductivity of boron-doped μc-Si, with emphasis on low doping levels that are designed to compensate exactly these native donor-like defects. We describe the dark conductivity and the photoconductivity as functions of dark conductivity activation energy and the average boron concentration, and present a model for the photoconductivity based on band off sets between the crystalline and amorphous regions of the μc-Si.


2021 ◽  
Vol 7 (16) ◽  
pp. eabf7358
Author(s):  
Meng Peng ◽  
Runzhang Xie ◽  
Zhen Wang ◽  
Peng Wang ◽  
Fang Wang ◽  
...  

Blackbody-sensitive room-temperature infrared detection is a notable development direction for future low-dimensional infrared photodetectors. However, because of the limitations of responsivity and spectral response range for low-dimensional narrow bandgap semiconductors, few low-dimensional infrared photodetectors exhibit blackbody sensitivity. Here, highly crystalline tellurium (Te) nanowires and two-dimensional nanosheets were synthesized by using chemical vapor deposition. The low-dimensional Te shows high hole mobility and broadband detection. The blackbody-sensitive infrared detection of Te devices was demonstrated. A high responsivity of 6650 A W−1 (at 1550-nm laser) and the blackbody responsivity of 5.19 A W−1 were achieved. High-resolution imaging based on Te photodetectors was successfully obtained. All the results suggest that the chemical vapor deposition–grown low-dimensional Te is one of the competitive candidates for sensitive focal-plane-array infrared photodetectors at room temperature.


RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 98001-98009 ◽  
Author(s):  
Thais Chagas ◽  
Thiago H. R. Cunha ◽  
Matheus J. S. Matos ◽  
Diogo D. dos Reis ◽  
Karolline A. S. Araujo ◽  
...  

We have used atomically-resolved scanning tunneling microscopy and spectroscopy to study the interplay between the atomic and electronic structure of graphene formed on copper via chemical vapor deposition.


MRS Bulletin ◽  
2000 ◽  
Vol 25 (11) ◽  
pp. 21-30 ◽  
Author(s):  
Joel S. Miller ◽  
Arthur J. Epstein

Molecule-based magnets are a broad, emerging class of magnetic materials that expand the materials properties typically associated with magnets to include low density, transparency, electrical insulation, and low-temperature fabrication, as well as combine magnetic ordering with other properties such as photoresponsiveness. Essentially all of the common magnetic phenomena associated with conventional transition-metal and rare-earth-based magnets can be found in molecule-based magnets. Although discovered less than two decades ago, magnets with ordering temperatures exceeding room temperature, very high (∼27.0 kOe or 2.16 MA/m) and very low (several Oe or less) coercivities, and substantial remanent and saturation magnetizations have been achieved. In addition, exotic phenomena including photoresponsiveness have been reported. The advent of molecule-based magnets offers new processing opportunities. For example, thin-film magnets can be prepared by means of low-temperature chemical vapor deposition and electrodeposition methods.


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