First-principles study on intrinsic defects of SnSe

Huang, Yu‐Cheng; Wang, Chan; Chen, Xi; Zhou, Danmei; Du, Jinyan; Wang, Sufan; Ning, Lixing

doi:10.1039/c7ra03367b

Cited by 90 publications

(56 citation statements)

References 54 publications

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“…From a full geometry relaxation, the lattice constants of SnSe were predicted at a = 11.571 Å, b = 4.168 Å and c = 4.517 Å, which are in good agreement with the experimental values (a = 11.550, b = 4.153, and c = 4.450 Å). The optimized of Sn-Se bond lengths were calculated to be 2.78 and 2.83 Å, which also agree well earlier theoretical prediction 48 . The SnSe (100), (001), (011), and (111) surfaces surface were created from the optimized bulk material using the METADISE code 49 , which ensures the creation of surfaces with zero dipole moment perpendicular to the surface plane 50 .…”

Section: Resultssupporting

confidence: 89%

Enhanced Field Emission Properties of Au/SnSe Nano-heterostructure: A Combined Experimental and Theoretical Investigation

Rondiya

Jadhav

Chavan

et al. 2020

Sci Rep

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We report the field emission properties of two-dimensional SnSe nanosheets (NSs) and Au/SnSe nanoheterostructure (NHS) prepared by a simple and economical route of one-pot colloidal and sputtering technique. Field Emission Scanning Electron Microscope (FESEM) analysis reveal surface protrusions and morphology modification of the SnSe NSs by Au deposition. By decorating the SnSe NSs with Au nanoparticles, significant improvement in field emission characteristics were observed. A significant reduction in the turn-on field from 2.25 V/µm for the SnSe NSs to 1.25 V/µm for the Au/SnSe NHS was observed. Emission current density of 300 µA/cm 2 has been achieved at an applied field of 4.00 and 1.91 V/µm for SnSe NSs and Au/SnSe NHS, respectively. Analysis of the emission current as a function of time also demonstrated the robustness of the present Au/SnSe NHS. Consistent with the experimental data, our complementary first-principles DFT calculations predict lower work function for the Au/SnSe NHS compared to the SnSe NSs as the primary origin for improved field emission. The present study has evidently provided a rational heterostructure strategy for improving various field emission related applications via surface and electronic modifications of the nanostructures.

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Section: Resultssupporting

confidence: 89%

Enhanced Field Emission Properties of Au/SnSe Nano-heterostructure: A Combined Experimental and Theoretical Investigation

Rondiya

Jadhav

Chavan

et al. 2020

Sci Rep

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“…[40] The films exhibit Seebeck coefficients of a similar magnitude to those seen by Zhao et al at room temperature. [13] While in single-crystal SnSe, the Seebeck coefficient is seen to drop from ≈550 to ≈350 µV K −1 between 600 and 800 K, [13] for thermally evaporated thin films, the Seebeck coefficient is >600 µV K −1 at room temperature, but drops to ≈140 µV K −1 by 600 K with the drop starting at 460 K. This drop is more pronounced and at lower temperatures compared to single-crystal SnSe.…”

Section: Thermoelectricssupporting

confidence: 67%

Thin Film Tin Selenide (SnSe) Thermoelectric Generators Exhibiting Ultralow Thermal Conductivity

et al. 2018

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Tin selenide (SnSe) has attracted much attention in the field of thermoelectrics since the discovery of the record figure of merit (ZT) of 2.6 ± 0.3 along the b‐axis of the material. The record ZT is attributed to an ultralow thermal conductivity that arises from anharmonicity in bonding. While it is known that nanostructuring offers the prospect of enhanced thermoelectric performance, there have been minimal studies in the literature to date of the thermoelectric performance of thin films of SnSe. In this work, preferentially orientated porous networks of thin film SnSe nanosheets are fabricated using a simple thermal evaporation method, which exhibits an unprecedentedly low thermal conductivity of 0.08 W m−1 K−1 between 375 and 450 K. In addition, the first known example of a working SnSe thermoelectric generator is presented and characterized.

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“…Based on the DFT calculations, it has been reported that both V Se and V Sn + 2V Se produce only localized electrons and do not contribute to band transport in SnSe [24]. While V Se can behave as both a donor and an acceptor depending on the Fermi level [23], the complex defects (V Sn + nV Se ) tend to be acceptors. This is indicated by the transport measurements (increase in the hole concentration) presented in Sec.…”

Section: A Positron Annihilation Spectroscopymentioning

confidence: 99%

“…Recently, more particular attention has been given to intrinsic defects (IDs) [15,[21][22][23]. The intrinsic defects, e.g., Sn vacancies (V Sn ), seem to play a very important role in the excellent electronic properties of SnSe at elevated temperatures [15,24].…”

Section: Introductionmentioning

confidence: 99%

Vacancies in SnSe single crystals in a near-equilibrium state

et al. 2019

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The development of intrinsic vacancies in SnSe single crystals was investigated as a function of annealing temperature by means of positron annihilation spectroscopy accompanied by transport measurements. It has been demonstrated that two types of vacancies are present in single-crystalline SnSe. While Sn vacancies dominate in the low-temperature region, Se vacancies and vacancy clusters govern the high-temperature region. These findings are supported by theoretical calculations enabling direct detection and quantification of the most favorable type of vacancies. The experiments show that Sn vacancies couple with one or more Se vacancies with increasing temperature to form vacancy clusters. Interestingly, the clusters survive the α→β transition at ≈800 K and even grow in size with temperature. The concentration of both Se vacancies and vacancy clusters increases with temperature, similar to thermoelectric performance. This indicates that the extraordinary thermoelectric properties of SnSe are related to point defects. We suggest that either these defects vary the band structure in favor of high thermoelectric performance or introduce an energy-dependent scattering of free carriers realizing, in fact, energy filtering of the free carriers. Cluster defects account for the glasslike thermal conductivity of SnSe at elevated temperatures.

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First-principles study on intrinsic defects of SnSe

Abstract: Sn vacancies can work as an effective source for p-type conduction under both Sn- and Se-rich conditions while n-type conduction is unlikely to be realized due to the absence of the effective intrinsic source.

Cited by 90 publications

References 54 publications

Enhanced Field Emission Properties of Au/SnSe Nano-heterostructure: A Combined Experimental and Theoretical Investigation

Enhanced Field Emission Properties of Au/SnSe Nano-heterostructure: A Combined Experimental and Theoretical Investigation

Thin Film Tin Selenide (SnSe) Thermoelectric Generators Exhibiting Ultralow Thermal Conductivity

Vacancies in SnSe single crystals in a near-equilibrium state

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