Wenkai Zhu; Faguang Yan; Quanshan Lv; Ce Hu; Kaiyou Wang
Abstract
Photodetectors based on two-dimensional (2D) materials and their heterostructures have been attracting immense research interests due to their excellent device performances, such as ultrahigh photoresponsivity, ultrafast and broadband photodetection, polarized sensitivity, flexibility, and Complementary ...
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Photodetectors based on two-dimensional (2D) materials and their heterostructures have been attracting immense research interests due to their excellent device performances, such as ultrahigh photoresponsivity, ultrafast and broadband photodetection, polarized sensitivity, flexibility, and Complementary Metal-Oxide-Semiconductor (CMOS) compatibility. Here, we firstly compare the device performance of several photodetectors based on Schottky junctions and p-n junctions, such as photoresponsivity and response time. Then, we provide an overview of the recent progress on 2D material-based photodetectors, emerging strategies to improve device performances by structure optimization and bandgap engineering as well. Finally, we discuss the challenges and perspectives on the exploration of 2D materials and their heterostructures for future application in electronics and optoelectronics.
Matko Mužević; Maja Varga Pajtler; Sanjeev Kumar Gupta; Igor Lukačević
Abstract
Optical properties of 2D materials can be effectively modulated by employing multilayer structures with different number of layers. Using the theoretical approach based on density functional theory we simulated relevant optical spectra of antimony and indium mono- and multilayers. We showed that the ...
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Optical properties of 2D materials can be effectively modulated by employing multilayer structures with different number of layers. Using the theoretical approach based on density functional theory we simulated relevant optical spectra of antimony and indium mono- and multilayers. We showed that the electronic band structures of antimonene and indiene possess numerous tracking bands enhancing the transition probability. Therefore, high absorption coefficients are found. Modelled multilayer nanostructures of antimonene and indiene experience a red-shift of absorption bands. Antimonene exhibits an optical directional anisotropy regarding the absorbance coefficient and reflectance spectrum for different nanolayer thicknesses. Indiene possesses very high reflectance and refractive index in the visible and IR spectrum which can be effectively modulated by the number of layers. Our work shows that antimonene and indiene multilayers harbour untapped potential for the optical applications at the nanoscale.

T Chaitanya Sagar; Viswanath R Chinthapenta
Abstract
In the current study, elastic properties of stanene, a hexagonal honeycomb allotrope of tin is investigated using tools in computational material science. The simulations are performed using Quantum Espresso, an open-source package suit used for conducting ab-initio density functional theory simulations. ...
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In the current study, elastic properties of stanene, a hexagonal honeycomb allotrope of tin is investigated using tools in computational material science. The simulations are performed using Quantum Espresso, an open-source package suit used for conducting ab-initio density functional theory simulations. The lattice structure of stanene analogous to the other group-IV elements 2D structures like graphene, silicene, and germanene. The relaxed structure of stanene in hexagonal honeycomb structure is found to have a lattice parameter . Unlike pristine graphene which has no buckling, stanene structure shows a buckling . All the calculations are carried out using generalized gradient approximation (GGA), and the exchange-correlation is treated using Perdew-Burke-Ernzerhof (PBE) functional. The cohesive energy of the structure is found to be . The calculations are conducted at groundstate without the inclusion of spin orbit coupling. The band structure, total and partial density of states at the ground state reveal the conducting nature of stanene. In addition, the second order elastic constants evaluated are reported and compared with the -tin and -tin counterparts.
