scholarly journals Strain engineering and lattice vibration manipulation of atomically thin TaS2 films

RSC Advances ◽  
2020 ◽  
Vol 10 (28) ◽  
pp. 16718-16726
Author(s):  
Xing Wu ◽  
Yongqing Cai ◽  
Jihong Bian ◽  
Guohui Su ◽  
Chen Luo ◽  
...  

We observed lattice vibration modulation in strained mono- and few-layer tantalum sulfide. E1g and E2g exhibit sensitive strain dependence with the frequency of the former intensity increasing and the latter decreasing under a compressive strain.

2021 ◽  
Author(s):  
Sanghamitra Das ◽  
Taraprasanna Dash ◽  
Devika Jena ◽  
Eleena Mohapatra ◽  
C K Maiti

Abstract In this work, we present a physics-based analysis of two-dimensional electron gas (2DEG) sheet carrier density and other microwave characteristics such as transconductance and cutoff frequency of AlxGa1-xN/GaN high electron mobility transistors (HEMT). An accurate polarization-dependent charge control-based analysis is performed for microwave performance assessment in terms of current, transconductance, gate capacitances, and cutoff frequency of lattice-mismatched AlGaN/GaN HEMTs. The influence of stress on spontaneous and piezoelectric polarization is included in the simulation of an AlGaN/GaN HEMT. We have shown the change in threshold voltage (Vt) due to tensile and compressive strain with different gate lengths. Also, the influence of stress due to the change in nitride thickness is presented. Our simulation results for drain current, transconductance, and current-gain cutoff frequency for various gate length devices are calibrated and verified with experimental data over a wide range of gate and drain applied voltages, which are expected to be useful for microwave circuit design. The predicted transconductance, drain conductance, and operation frequency are quite close to the experimental data. The AlGaN/GaN heterostructure HEMTs with nitride passivation layers show great promise as a candidate in future high speed and high power applications.


Author(s):  
Hiroshi Kawakami ◽  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura

A new highly sensitive strain measurement method has been developed by applying the strain-induced change of the electronic conductivity of CNTs. It is reported that most multi-walled carbon nanotubes (MWCNTs) show metallic conductivity and they are rather cheap comparing with single-walled carbon nanotubes (SWCNTs). However, it was found that the electric conductivity of MWCNTs changes drastically under uniaxial strain because of the drastic change of their band gap. Therefore, the authors have developed a highly sensitive strain sensor which can detect the local strain distribution by using MWCNTs. In order to design a new sensor using MWCNT, it is very important to control the shape of the MWCNTs under strain. Thus, a method for controlling the shape of the MWCNTs was developed by applying a chemical vapor deposition (CVD) technique. It was found that the shape of the grown MWCNT could be controlled by changing the average thickness of the catalyst and the deposition temperature of the MWCNT. The electrical resistance of the grown MWCNT changed almost linearly with the applied strain, and the maximum strain sensitivity obtained under the application of uniaxial strain was about 10%/1000-μstrain (gauge factor: 100). A two-dimensional strain sensor, which consists of area-arrayed fine bundles of MWCNTs, has been developed by applying MEMS technology. Under the application of compressive strain, the electric resistance was confirmed to increase almost linearly with the applied strain.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4945
Author(s):  
Li-Hua Qu ◽  
Xiao-Long Fu ◽  
Chong-Gui Zhong ◽  
Peng-Xia Zhou ◽  
Jian-Min Zhang

We report first-principles calculations on the structural, mechanical, and electronic properties of O2 molecule adsorption on different graphenes (including pristine graphene (G–O2), N(nitrogen)/B(boron)-doped graphene (G–N/B–O2), and defective graphene (G–D–O2)) under equibiaxial strain. Our calculation results reveal that G–D–O2 possesses the highest binding energy, indicating that it owns the highest stability. Moreover, the stabilities of the four structures are enhanced enormously by the compressive strain larger than 2%. In addition, the band gaps of G–O2 and G–D–O2 exhibit direct and indirect transitions. Our work aims to control the graphene-based structure and electronic properties via strain engineering, which will provide implications for the application of new elastic semiconductor devices.


2015 ◽  
Vol 26 (46) ◽  
pp. 465707 ◽  
Author(s):  
Liyan Zhu ◽  
Tingting Zhang ◽  
Ziming Sun ◽  
Jianhua Li ◽  
Guibin Chen ◽  
...  

2005 ◽  
Vol 87 (19) ◽  
pp. 192102 ◽  
Author(s):  
K. Sawano ◽  
Y. Abe ◽  
H. Satoh ◽  
Y. Shiraki ◽  
K. Nakagawa

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Wei Pan ◽  
Jianliang Xiao ◽  
Junwei Zhu ◽  
Chenxi Yu ◽  
Gang Zhang ◽  
...  

2016 ◽  
Vol 114 (1) ◽  
pp. E1-E8 ◽  
Author(s):  
Marziyeh Zamiri ◽  
Farhana Anwar ◽  
Brianna A. Klein ◽  
Amin Rasoulof ◽  
Noel M. Dawson ◽  
...  

Antimonide compounds are fabricated in membrane form to enable materials combinations that cannot be obtained by direct growth and to support strain fields that are not possible in the bulk. InAs/(InAs,Ga)Sb type II superlattices (T2SLs) with different in-plane geometries are transferred from a GaSb substrate to a variety of hosts, including Si, polydimethylsiloxane, and metal-coated substrates. Electron microscopy shows structural integrity of transferred membranes with thickness of 100 nm to 2.5 μm and lateral sizes from 24×24μm2 to 1×1 cm2. Electron microscopy reveals the excellent quality of the membrane interface with the new host. The crystalline structure of the T2SL is not altered by the fabrication process, and a minimal elastic relaxation occurs during the release step, as demonstrated by X-ray diffraction and mechanical modeling. A method to locally strain-engineer antimonide-based membranes is theoretically illustrated. Continuum elasticity theory shows that up to ∼3.5% compressive strain can be induced in an InSb quantum well through external bending. Photoluminescence spectroscopy and characterization of an IR photodetector based on InAs/GaSb bonded to Si demonstrate the functionality of transferred membranes in the IR range.


Nano Energy ◽  
2021 ◽  
pp. 106053
Author(s):  
Jie Wang ◽  
Yingjie Hu ◽  
Baifeng Yang ◽  
Xin Wang ◽  
Jinwen Qin ◽  
...  

2019 ◽  
Vol 5 (11) ◽  
pp. eaax8275 ◽  
Author(s):  
Gao-Feng Han ◽  
Xiang-Mei Shi ◽  
Seok-Jin Kim ◽  
Jeonghun Kim ◽  
Jong-Pil Jeon ◽  
...  

All quiet on the nitrogen front. The dissociation of stable diatomic nitrogen molecules (N2) is one of the most challenging tasks in the scientific community and currently requires both high pressure and high temperature. Here, we demonstrate that N2 can be dissociated under mild conditions by cyclic strain engineering. The method can be performed at a critical reaction pressure of less than 1 bar, and the temperature of the reaction container is only 40°C. When graphite was used as a dissociated N* receptor, the normalized loading of N to C reached as high as 16.3 at/at %. Such efficient nitrogen dissociation is induced by the cyclic loading and unloading mechanical strain, which has the effect of altering the binding energy of N, facilitating adsorption in the strain-free stage and desorption in the compressive strain stage. Our finding may lead to opportunities for the direct synthesis of N-containing compounds from N2.


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