A type-II C2N/α-Te van der Waals heterojunction with improved optical properties by external perturbation

2019 ◽  
Vol 21 (39) ◽  
pp. 21753-21760 ◽  
Author(s):  
Zhuang Ma ◽  
Yusheng Wang ◽  
Yuting Wei ◽  
Chong Li ◽  
Xiuwen Zhang ◽  
...  

The C2N/α-Te vdW heterojunction possessed a unique type-II band alignment, tunable band gap, improved optical absorption strength, and broad spectrum width (ultraviolet to near-infrared).

2017 ◽  
Vol 5 (26) ◽  
pp. 13400-13410 ◽  
Author(s):  
Congxin Xia ◽  
Juan Du ◽  
Wenqi Xiong ◽  
Yu Jia ◽  
Zhongming Wei ◽  
...  

Type-II band alignment, a suitable direct gap (1.519 eV), superior optical-absorption (∼105) and a broad spectrum make the GeSe/SnS heterobilayer a promising material for photovoltaic applications.


2017 ◽  
Vol 5 (37) ◽  
pp. 9687-9693 ◽  
Author(s):  
Ning Wang ◽  
Dan Cao ◽  
Jun Wang ◽  
Pei Liang ◽  
Xiaoshuang Chen ◽  
...  

Antimonene/GaAs van der Waals heterostructures exhibit a type-II band alignment and a high optical absorption coefficient in the visible-light range.


2021 ◽  
Vol 23 (6) ◽  
pp. 3963-3973
Author(s):  
Jianxun Song ◽  
Hua Zheng ◽  
Minxia Liu ◽  
Geng Zhang ◽  
Dongxiong Ling ◽  
...  

The structural, electronic and optical properties of a new vdW heterostructure, C2N/g-ZnO, with an intrinsic type-II band alignment and a direct bandgap of 0.89 eV at the Γ point are extensively studied by DFT calculations.


2019 ◽  
Vol 61 (6) ◽  
pp. 1204
Author(s):  
Г.И. Миронов

AbstractThe electronic and optical properties of gold fullerenes are studied in the framework of the Hubbard model. The expressions of the Fourier transforms of anticommutator Green functions have been obtained for gold fullerenes Au_16 and Au_20, the poles of which determine the energy spectrum of the system under consideration. The calculations are performed for the thermodynamic means that characterize jumps of electrons from a nanosystem site to a neighboring site, the correlation functions demonstrating the possibility of existing two d electrons with oppositely oriented spin projections on the same site of the fullerenes consisting of gold atoms. The optical absorption spectra are presented. The optical absorption peaks of ions $${\text{Au}}_{{20}}^{ - }$$ and $${\text{Au}}_{{16}}^{ - }$$ correspond to a near-infrared spectral region, where the light absorption by blood or a soft tissue is vanishingly small; thus, these ions can be used as a new class of contrast improvements and phototherapeutic means for diagnostics and treatment of cancer.


2020 ◽  
Vol 10 (4) ◽  
pp. 1419 ◽  
Author(s):  
Sandhya Vasudevan ◽  
Farnoush Forghani ◽  
Chris Campbell ◽  
Savannah Bedford ◽  
Thomas D. O’Sullivan

A hybrid reflectance-based diffuse optical imaging (DOI) technique combining discrete wavelength frequency-domain (FD) near-infrared spectroscopy (NIRS) with broadband continuous wave NIRS measurements was developed to quantify the broadband optical properties of deep tumor-like inclusions. This method was developed to more accurately measure the broadband optical properties of human tumors using a compact handheld imaging probe and without requiring a priori spectral constraints. We simulated the reconstruction of absorption and scattering spectra (650–1000 nm) of human breast tumors in a homogeneous background at depths of 0 to 10 mm. The hybrid DOI technique demonstrated enhanced performance in reconstruction of optical absorption with a mean accuracy over all 71 wavelengths of 8.39% versus 32.26% for a 10 mm deep tumor with the topographic DOI method. The new hybrid technique was also tested and validated on two heterogeneous tissue-simulating phantoms with inclusion depths of 2, 7, and 9 mm. The mean optical absorption accuracy over all wavelengths was similarly improved up to 5x for the hybrid DOI method versus topographic DOI for the deepest inclusions.


2018 ◽  
Vol 7 (1) ◽  
pp. 35-41
Author(s):  
Garima Bhardwaj ◽  
Sandhya K. ◽  
Richa Dolia ◽  
M. Abu-Samak ◽  
Shalendra Kumar ◽  
...  

In this paper, we have configured InGaAsP QW (quantum well) heterostructures of type-I and type-II band alignments and simulated their optical characteristics by solving 6 x 6 Kohn-Luttinger Hamiltonian Matrix. According to the simulation results, the InGaAsP QW heterostructure of type-I band alignment has been found to show peak optical gain (TE mode) of the order of~3600/cm at the transition wavelength~1.40 µm; while of type-II band alignment has achieved the peak gain (TE mode) of the order of~7800/cm at the wavelength of~1.85 µm (eye safe region). Thus, both of the heterostructures can be utilized in designing of opto-or photonic devices for the emission of radiations in NIR (near infrared region) but form the high gain point of view, the InGaAsP of type-II band alignment can be more preferred.


2018 ◽  
Vol 6 (27) ◽  
pp. 7201-7206 ◽  
Author(s):  
Jimin Shang ◽  
Longfei Pan ◽  
Xiaoting Wang ◽  
Jingbo Li ◽  
Hui-Xiong Deng ◽  
...  

2D InSe/InTe van der Waals heterostructures with a direct band structure and typical type-II band alignment, effectively tuned by applying normal strain, are systematically discussed for future optoelectronic devices.


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