scholarly journals A Theoretical and Simulation Analysis of the Sensitivity of SiNWs-FET Sensors

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 121
Author(s):  
Yi Yang ◽  
Zicheng Lu ◽  
Duo Liu ◽  
Yuelin Wang ◽  
Shixing Chen ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface State ◽  
Surface Defects ◽  
Theoretical Study ◽  
Simulation Analysis ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Software Simulation ◽  
Effect Transistor

Theoretical study and software simulation on the sensitivity of silicon nanowires (SiNWs) field effect transistor (FET) sensors in terms of surface-to-volume ratio, depletion ratio, surface state and lattice quality are carried out. Generally, SiNWs-FET sensors with triangular cross-sections are more sensitive than sensors with circular or square cross-sections. Two main reasons are discussed in this article. Firstly, SiNWs-FET sensors with triangular cross-sections have the largest surface-to-volume ratio and depletion ratio which significantly enhance the sensors’ sensitivity. Secondly, the manufacturing processes of the electron beam lithography (EBL) and chemical vapor deposition (CVD) methods seriously affect the surface state and lattice quality, which eventually influence SiNWs-FET sensors’ sensitivity. In contrast, wet etching and thermal oxidation (WETO) create fewer surface defects and higher quality lattices. Furthermore, the software simulation confirms that SiNWs-FET sensors with triangular cross-sections have better sensitivity than the other two types of SiNWs-FET sensors under the same conditions, consistent with the theoretical analysis. The article fully proved that SiNWs-FET sensors fabricated by the WETO method produced the best sensitivity and it will be widely used in the future.

scholarly journals High-performance monolayer MoS2 photodetector enabled by oxide stress liner using scalable chemical vapor growth method

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1981-1991 ◽  
Author(s):  
Zhiwen Li ◽  
Jing Wu ◽  
Cong Wang ◽  
Han Zhang ◽  
Wenjie Yu ◽  
...  
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Surface Defects ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Light Illumination ◽  
Vapor Growth ◽  
Layer Deposition ◽  
Growth Method

AbstractMoS2, as a typical representative of two-dimensional semiconductors, has been explored extensively in applications of optoelectronic devices because of its adjustable bandgap. However, to date, the performance of the fabricated photodetectors has been very sensitive to the surrounding environment owing to the large surface-to-volume ratio. In this work, we report on large-scale, high-performance monolayer MoS2 photodetectors covered with a 3-nm Al2O3 layer grown by atomic layer deposition. In comparison with the device without the Al2O3 stress liner, both the photocurrent and responsivity are improved by over 10 times under 460-nm light illumination, which is due to the tensile strain induced by the Al2O3 layer. Further characterization demonstrated state-of-the-art performance of the device with a responsivity of 16.103 A W−1, gain of 191.80, NEP of 7.96 × 10−15 W Hz−1/2, and detectivity of 2.73 × 1010 Jones. Meanwhile, the response rise time of the photodetector also reduced greatly because of the increased electron mobility and reduced surface defects due to the Al2O3 stress liner. Our results demonstrate the potential application of large-scale strained monolayer MoS2 photodetectors in next-generation imaging systems.

Influence of Defects on the Young's Modulus of [110] Silicon Nanowires with Different Cross Sections

2015 ◽  
Vol 645-646 ◽  
pp. 151-156
Author(s):  
Fang Gu ◽  
Jia Hong Zhang ◽  
Min Li ◽  
Lin Yan Liu ◽  
Jing Su
Keyword(s):  
Young’S Modulus ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Defects ◽  
Young's Modulus ◽  
High Surface ◽  
Surface Effects ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Induced Defects

The size dependence becomes more significant as the devices scale down from micro-to nanodimensions, which is generally attributed to surface effects due to the very high surface-to-bulk ratios in nanoscale structures. However, significant discrepancies between experimental measurements and computational studies indicate that there could be other influences besides surface effects, such as the influences of native oxide layer, fabrication-induced defects and boundary conditions. In this paper, our purpose is to investigate mainly the influence of fabrication-induced defects on the elasticity of [110] silicon nanowires (SiNWs) with different cross sections. We accomplish this by using the molecular dynamics (MD) simulation. Our MD results show that the H-passivated [110] SiNWs without surface defects is slightly elastically softer than bulk, which is in good agreement with other literature MD values. However, the effective Young’s modulus of SiNWs with surface defects can significantly decreases as the defects increase. This softening behavior of [110] SiNWs is severe, which indicates the importance of surface defects. It is noted that the influence of defects on the Young's Modulus of SiNWs strongly depended on the distribution and morphology of defects as well as the cross-sectional shapes of SiNWs. It is observed that the influence of defects on square SiNWs is significantly different from those of hexagonal and triangle SiNWs. Our work reveals that fabrication-induced surface defects could be one of the important origins of the reduced effective Young’s modulus experimentally observed in ultra-thin SiNWs. Therefore, the effect of defects on the characterization of the mechanical properties of nanowire must be carefully considered.

Acceptor Deactivation in Silicon Nanowires Analyzed by Scanning Spreading Resistance Microscopy

2011 ◽  
Vol 178-179 ◽  
pp. 50-55
Author(s):  
Reinhard Kögler ◽  
Xin Ou ◽  
Nadine Geyer ◽  
Pratyush Das Kanungo ◽  
Daniel Schwen ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Effect ◽  
Bulk Material ◽  
Electrical Characterization ◽  
Volume Ratio ◽  
Ex Situ ◽  
Analysis Method ◽  
Si Nanowires ◽  
Spreading Resistance

Vertical p-type Si nanowires (NWs) "in-situ" doped during growth or "ex-situ" by B ion implantation are investigated regarding their acceptor activation. Due to the much higher surface to volume ratio of the NW in comparison to bulk material the surface effect plays an important role in determining the doping behaviour. Dopant segregation and fixed positive charges at the Si/SiO2 interface result in an acceptor deactivation. The B concentration introduced into the NW has to balance the deactivation effects in order to reach the intended electrical parameters. Scanning spreading resistance microscopy is used for the electrical characterization of the NWs. This analysis method provides images of the local resistivity of NW cross sections. Resistivity data are converted into acceptor concentration values by calibration. The study demonstrates that scanning spreading resistance microscopy is a suitable analysis method capable to spatially and electrically resolve Si NWs in the nanometer-scale. The NW resistivity is found to be size dependent and shows a significant increase as the NW is below 25 nm in diameter. The obtained data can be explained by a core-shell model with a highly conductive NW core and low conductive shell.

Characterization of homoepitaxial diamond films by Electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 880-881
Author(s):  
D.P. Malta ◽  
S.A. Willard ◽  
R.A. Rudder ◽  
G.C. Hudson ◽  
J.B. Posthill ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Substrate Surface ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Large Degree ◽  
Rf Plasma ◽  
Semiconducting Diamond

Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. A major goal of current device-related diamond research is to achieve a high quality epitaxial film on an inexpensive, readily available, non-native substrate. One step in the process of achieving this goal is understanding the nucleation and growth processes of diamond films on diamond substrates. Electron microscopy has already proven invaluable for assessing polycrystalline diamond films grown on nonnative surfaces.The quality of the grown diamond film depends on several factors, one of which is the quality of the diamond substrate. Substrates commercially available today have often been found to have scratched surfaces resulting from the polishing process (Fig. 1a). Electron beam-induced current (EBIC) imaging shows that electrically active sub-surface defects can be present to a large degree (Fig. 1c). Growth of homoepitaxial diamond films by rf plasma-enhanced chemical vapor deposition (PECVD) has been found to planarize the scratched substrate surface (Fig. 1b).

Effect of Metal - Silicon Nanowire Contacts on the Performance of Accumulation Metal Oxide Semiconductor Field Effect Transistor

2008 ◽  
Vol 1144 ◽  
Author(s):  
Pranav Garg ◽  
Yi Hong ◽  
Md. Mash-Hud Iqbal ◽  
Stephen J. Fonash
Keyword(s):  
Metal Oxide ◽  
Silicon Nanowires ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Silicon Nanowire ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Manufacturing Cost ◽  
Effect Transistor ◽  
The Impact

ABSTRACTRecently, we have experimentally demonstrated a very simply structured unipolar accumulation-type metal oxide semiconductor field effect transistor (AMOSFET) using grow-in-place silicon nanowires. The AMOSFET consists of a single doping type nanowire, metal source and drain contacts which are separated by a partially gated region. Despite its simple configuration, it is capable of high performance thereby offering the potential of a low manufacturing-cost transistor. Since the quality of the metal/semiconductor ohmic source and drain contacts impacts AMOSFET performance, we repot here on initial exploration of contact variations and of the impact of thermal process history. With process optimization, current on/off ratios of 106 and subthreshold swings of 70 mV/dec have been achieved with these simple devices

scholarly journals Passivation of high aspect ratio silicon nanowires by using catalytic chemical vapor deposition for radial heterojunction solar cell application

RSC Advances ◽  
2017 ◽  
Vol 7 (71) ◽  
pp. 45101-45106 ◽  
Author(s):  
Gangqiang Dong ◽  
Yurong Zhou ◽  
Hailong Zhang ◽  
Fengzhen Liu ◽  
Guangyi Li ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Aspect Ratio ◽  
Silicon Nanowires ◽  
Vapor Deposition ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Chemical Vapor ◽  
Solar Cell Application ◽  
Catalytic Chemical Vapor Deposition ◽  
Metal Assisted Chemical Etching

High aspect ratio silicon nanowires (SiNWs) prepared by metal-assisted chemical etching were passivated by using catalytic chemical vapor deposition (Cat-CVD).

Wafer-Scale, Highly-Ordered Silicon Nanowires Produced by Step-and-Flash Imprint Lithography and Metal-Assisted Chemical Etching

2012 ◽  
Vol 1512 ◽  
Author(s):  
Jian-Wei Ho ◽  
Qixun Wee ◽  
Jarrett Dumond ◽  
Li Zhang ◽  
Keyan Zang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Semiconductor Device ◽  
Imprint Lithography ◽  
Wafer Level ◽  
Conventional Photolithography ◽  
Metal Assisted Chemical Etching

ABSTRACTA combinatory approach of Step-and-Flash Imprint Lithography (SFIL) and Metal-Assisted Chemical Etching (MacEtch) was used to generate near perfectly-ordered, high aspect ratio silicon nanowires (SiNWs) on 4" silicon wafers. The ordering and shapes of SiNWs depends only on the SFIL nanoimprinting mould used, thereby enabling arbitary SiNW patterns not possible with nanosphere and interference lithography (IL) to be generated. Very densely packed SiNWs with periodicity finer than that permitted by conventional photolithography can be produced. The height of SiNWs is, in turn, controlled by the etching duration. However, it was found that very high aspect ratio SiNWs tend to be bent during processing. Hexagonal arrays of SiNW with circular and hexagonal cross-sections of dimensions 200nm and less were produced using pillar and pore patterned SFIL moulds. In summary, this approach allows highlyordered SiNWs to be fabricated on a wafer-level basis suitable for semiconductor device manufacturing.

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