Improved Electronic Structure and Optical Performance of Bi2Te3-xSex From First-principle Calculations Within TB-mBJ Exchange Potential

Abstract

Using the first-principle calculations of density functional theory within the (FP-LAPW) method, we have investigated the structural, electronic and optical properties of Bi 2 Te 3-x Se x alloys with compositions x = 0, 1, 2 and 3 of Se. The generalized gradient approximation functional of Wu and Cohen (GGA-PBE) is used to calculate ground state structural parameters of Bi 2 Te 3-x Se x , which are in good agreement with theoretical and experimental data. The electronic band structures and optical constants have been improved with Tran-Blaha modified Becker-Johnson (TB-mBJ) parameterization scheme. Also, we have analyzed in detail the performance of dielectric function, refractive index, reflectivity and optical conductivity of these alloys. Our results show that Bi 2 Te 3-x Se x alloys are promising candidates for optoelectronic applications especially in the Infrared and visible fields. Bi 2 Te 3-x Se x materials have a direct band gap and can be tuned from 0.1706 eV to 0.7819 eV by varying In composition so emission was tunable from 1.58 to 7.26 micrometers (infrared field), in addition for their direct band gap and in view of their attractive optical properties such conductivity, absorption and reflectivity these materials is considered as promising materials for optoelectronic applications.

The Cs2AgRhCl6 Halide Double Perovskite: A Dynamically Stable Lead-Free Transition-Metal Driven Semiconducting Material for Optoelectronics

“…The maximum of 38-45% light is likely to be reflected at the peak positions around 2.1 eV, and it is 15-25% around the onset of absorption. The reflectivity spectra of other systems reported elsewhere have similar characteristics (Peng et al, 2013;Ma et al, 2014;Saini et al, 2017;Mohamed et al, 2018). The energy loss function is plotted in Figure 5D.…”

Self-Biased High-Responsivity Photodetector Based on a Bi2SeTe2 Topological Insulator

“…Optoelectronic Performance in the Visible Region. Owing to the broadband light absorption of Bi-and Sb-based TIs, 21,36 our Bi 2 SeTe 2 photodetector demonstrates excellent photoresponse behavior throughout the visible region. First, we measured the I ds − V ds characteristics of the device with the shorter channel length of 3 μm under different illumination wavelengths and power densities (Figure 4a).…”

“…Further spectral photoresponse analysis finds that the Bi photodetector exhibits a relatively weak sensitivity to 488 nm illumination because of an oscillation in the absorption of Bi 2 SeTe 2 in the corresponding energy range. 21 The observed responsivity, which is 1 order of magnitude higher than for most individual TI-based self-biased photodetectors to date, coupled with the response time shorter than 40 ms, makes the photodetector one of the quickest among devices based only on topological insulators.…”

Bi2Te2Se and Sb2Te3 heterostructure based photodetectors with high responsivity and broadband photoresponse: experimental and theoretical analysis

“…Berber Mohamed et al have reported that Bi 2 Te 3Àx Se x alloys are coveted recruits for optoelectronic application in the infrared and visible regions. 23 According to Hongliang Shi et al, Bi 2 Te 2 Se and Bi 2 Te 3 have complex band structures, particularly non-parabolic isoenergy surfaces, which are advantageous for obtaining highperformance thermoelectrics. 24 The performance of photodetection can be enhanced by using heterostructures with 2D materials and TIs.…”