Broadband THz radiation emission from photoexcited GaSb1-xBix (0 &lt; x &lt; 1.65%) was investigated. We observed an enhancement in the THz emission with Bi incorporation in GaSb. GaSb1-xBix alloy with showed an emission amplitude comparable to that from LT-GaAs, which is over an order of magnitude higher compared to GaSb. Transient photocurrents due to p-type surface band bending was found to be the dominant emission mechanism in these alloys. Strengthening of the surface field due to Bi induced p-doping is responsible for the observed enhancement. The NIR pump incident angle and THz detection angle study suggests that the photocarrier momentum is preferentially aligned along the refracted excitation beam direction inside the semiconductor alloy. GaSb1-xBix emitter showed better spectral performance compared to a commercially available photoconductive antenna in a THz time domain spectroscopy system. This demonstrates the application potential of this material in THz spectroscopy. © 2018 IOP Publishing Ltd.

C P VAISAKH

M K BHOWAL

S DHAR

R N KINI

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Journal of Physics D: Applied Physics

Quantum dielectric Theory (QDT) is used to explain the band gap bowing effect observed in III-V-Bismides such as InSb1-xBix, InAs1-xBix, InP1-xBix, GaSb1-xBix, GaAs1-xBix and GaP1-xBix. The dependence of the direct E0 band gap for these alloys on Bi mole fraction is calculated using QDT which requires the evaluation of the bowing parameter c. The bowing parameter gives the deviation of the direct E0 band gap from the linear relationship of E0 with Bi mole fraction. The band gap reduction values obtained using QDT are compared with those calculated using Virtual Crystal approximation (VCA) and Valence Band Anticrossing (VBAC) model as well as with the reported experimental data and the results of the comparison shows excellent agreement. © 2015 Elsevier B.V. All rights reserved.

Physica B: Condensed Matter

Estimation of Bi induced changes in the direct E0 band gap of III-V-Bi alloys and comparison with experimental data

The effect of post-growth anneal on the photoluminescence (PL) properties of GaSbBi layers, grown by liquid phase epitaxy, is investigated. It is observed that annealing for temperatures up to 650 °C increases the PL intensity and decreases the PL peak width indicating an improvement in the crystalline quality of the layer. A second peak at 0.72 eV, observed in GaSbBi only, is totally removed by annealing, suggesting that the peak is related to emission from Bi-related antisite defects. A red shift of up to 9 meV is also observed for the band edge emission peak as a result of anneal. © 2014 IOP Publishing Ltd.

Journal	Journal of Physics D: Applied Physics
Publisher	Institute of Physics Publishing
ISSN	0022-3727