Strain dependence of the thermoelectric performance of porous armchair silicene nanoribbons
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Strain dependence of the thermoelectric performance of porous armchair silicene nanoribbons Sukhdeep Kaur1, Deep Kamal Kaur Randhawa2, Sukhleen Bindra Narang1,a) 1
Department of Electronics Technology, Guru Nanak Dev University, Amritsar, Punjab 143005, India Department of Electronics and Communication Engineering, Guru Nanak Dev University, RC Jalandhar, Ladhewali, Punjab 144007, India a) Address all correspondence to this author. e-mail: [email protected] 2
Received: 3 August 2019; accepted: 3 October 2019
In this article, the strain-dependent thermoelectric performance of circular porous armchair silicene nanoribbons (ASiNRs) under uniaxial tension and compression is computed by means of a semiempirical approach in combination with nonequilibrium Green’s function. Our findings clearly demonstrate that the thermoelectric performance can be effectively tuned by the optimum choice of the nature and magnitude of the strain depending on the pore size. For smaller pore sizes, higher tensile strains can be preferred whereas for nanostructures with larger pores, the compression is a suitable option. Further analysis concludes that the tensile deformation fails to attain any improvement in the thermoelectric figure of merit ZT at any choice of temperature, whereas the performance under compressive deformation goes on improving with the increase in the applied temperature. In addition, changing the pore shape to a triangular one is found to significantly enhance the thermoelectric performance.
Introduction The discovery of graphene and the subsequent work have inspired the investigation of two-dimensional compounds made from elements other than carbon. In particular, silicene, a monolayer of silicon atoms arranged in a honeycomb lattice, has gathered considerable excitement because of silicon’s central role in the semiconductor industry [1, 2]. Like graphene, it is also a zero–band gap semiconductor, with charge carriers as massless Dirac fermions, which leads to a very high carrier mobility. Both theoretical and experimental studies show that silicene possesses longer bond lengths and a slight buckled structure which is different from the planar structure of graphene [3]. Although C and Si belong to the same group of the periodic table, Si has a larger ionic radius which promotes sp3 hybridization. Quasi one-dimensional nanostructured materials derived from silicene, called silicene nanoribbons (SiNRs), have received an increasing amount of interest because of their electronic, magnetic, and thermal properties. One advantage of silicene over graphene is that it is expected to be compatible with existing silicon-based electronics [4]. Although significant research in the field of graphene nanoribbons is growing rapidly, its integration into current Si-
ª Materials Research Society 2019
based technologies faces a challenge [5]. If silicene nanoribbons could be grown, their integration into Si-based nanoelectronics would be favored over graphene which will offer potential advantages of performance enhancement in high-spe
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