Enhancement of the thermoelectric performance of bulk SnTe alloys via the synergistic effect of band structure modification and chemical bond softening

Wang, Hongchao; Hwang, Junphil; Zhang, Chao; Wang, Teng; Su, Weizhou; Kim, Hoon; Kim, Jungwon; Zhai, Jiqiang; Wang, Xue; Park, Hwanjoo; Kim, Woochul; Wang, Chunlei

doi:10.1039/c7ta03359a

Cited by 69 publications

(41 citation statements)

References 56 publications

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“…Raman spectra were also used to characterize the SnTe nanoflakes, as shown in Figure d. Clearly, the two characteristic vibration modes A 1 (optical phonon) and E TO (transverse optical phonon) located at 133 ± 2 cm −1 and 139 ± 3 cm −1 are determined, in agreement with previous reported results . An unpolarized scattering peak was also observed at 60 cm −1 in samples of (100) surface orientations.…”

Section: Comparison Of the Photoresponse Performance Of Our Snte Photsupporting

confidence: 88%

Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

Yang

Pan

et al. 2018

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Topological crystalline insulators (TCIs) are predicted to be a promising candidate material for ultra-broadband photodetectors ranging from ultraviolet (UV) to terahertz (THz) due to its gapless surface state and narrow bulk bandgap. However, the low responsivity of TCIs-based photodetectors limits their further applications. In this regard, a high-performance photodetector based on SnTe, a recently developed TCI, working in a broadband wavelength range from deep UV to mid-IR with high responsivity is reported. By taking advantage of the strong light absorption and small bandgap of SnTe, photodetectors based on the as-grown SnTe crystalline nanoflakes as well as specific short channel length achieve a high responsivity (71.11 A W at 254 nm, 49.03 A W at 635 nm, 10.91 A W at 1550 nm, and 4.17 A W at 4650 nm) and an ultra-broad spectral response (254-4650 nm) simultaneously. Moreover, for the first time, a durable flexible SnTe photodetector fabricated directly on a polyethylene terephthalate film is demonstrated. These results prove the great potential of TCIs as a promising material for integrated and flexible optoelectronic devices.

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Section: Comparison Of the Photoresponse Performance Of Our Snte Photsupporting

confidence: 88%

Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

Yang

Pan

et al. 2018

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“…For the Sn doped samples, similar Raman spectra can be observed, nevertheless, the band centered at 120 cm −1 shifts to 118 cm −1 . This signal has been assigned to the A 1 vibrational mode of Sn-Te [23]. The appearance of the Sn-Te vibrational mode as Sn ion density increases indicates that there exist Sn atoms substituting Cd in the CdTe lattice, which is in agreement with XRD results.…”

Section: Resultssupporting

confidence: 85%

CdTe:Sn thin films deposited by the simultaneous laser ablation of CdTe and Sn targets

Rivera

García

Cardona

et al. 2020

Mater. Res. Express

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CdTe:Sn thin films were grown by pulsed laser deposition on glass substrates at room temperature. The study of the changes in the chemical, structural and optical properties of the films as a function of the density of Sn ions calculated from Langmuir planar probe measurments is presented. Four films were grown by the simultaneous ablation of CdTe and Sn targets in vacuum. The Sn ion density was modified by varying the fluence on the Sn target, while the CdTe plasma density was kept constant for all the deposits. One CdTe film was grown as control sample using the same experimental conditions as in the CdTe:Sn films. The chemical composition was analyzed by XPS, where a dependence of the Sn incorporation into the CdTe lattice, on the Sn ion plasma density was demonstrated. The crystalline structure analysis by XRD showed a hexagonal structure for all the films. When the CdTe and Sn plasmas were combined, a preferential orientation in the plane (110) was observed for the resulting films. Furthermore, as Sn plasma density increased, the intensity of the (110) peak increased as well, suggesting that crystalline re-orientation is an effect of Sn incorporated into the CdTe lattice. Vibrational behavior was analyzed by Raman spectroscopy. A vibrational mode appeared at 118 cm −1 and was related to a Sn-Te vibration, suggesting the incorporation of substitutional Sn into the CdTe lattice. The Sn-Te bonding was confirmed by XPS by the appearance of signals centered at 485 and 494 eV, which correspond to Sn 2+ in SnTe. Thin films thicknesses values were between 320 and 460 nm increasing with Sn ion density. The band gap calculated using UV-vis spectrophotometry, resulted in values ranging from 1.42 to 1.46 eV. PL measurements showed a slight blue shift of the near-edge emission as Sn plasma density increased.

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“…Specifically, S increases by about 61% (from 177.9 to 286.5 µV K −1 ), σ increases by about 25.3% (from 5.7 × 10 3 to 7.2 × 10 3 S m −1 ), and κ decreases by about 36% (from 4.4 ± 1.8 to 2.8 ± 1.0 W m −1 K −1 ) upon heating from 300 to 500 K. The increase of S and σ, combined with the reduction of κ, enhance the PF and TE ZT. As a result, PF increases from 181.9 to 591.1 µW m −1 K −2 , and a ZT value of 0.183 for SnTe thin film is achieved at 500 K, which is significantly higher than previously reported values for undoped SnTe in the same temperature range, as presented in Figure . We note that ZT increased by a factor of 7.5 times from 300 to 500 K. The enhancement of ZT is presumably due to nanosizing, lattice defects, and the anisotropic geometry of the nanorods.…”

Section: Resultsmentioning

confidence: 41%

“…The nanostructuring approach has shown promise for allowing SnS, SnSe, and SnTe NCs to achieve competitive TE performance . Doping and alloying tin(II) chalcogenides with metals or metal chalcogenides, which results in increased phonon scattering or a controllable n , provides another way to optimize ZT . In this work, we report a facile and low‐cost colloidal route to synthesize tin(II or IV) chalcogenide NCs with controlled vacancy concentrations and morphologies.…”

Section: Introductionmentioning

confidence: 99%

Controllable Colloidal Synthesis of Tin(II) Chalcogenide Nanocrystals and Their Solution‐Processed Flexible Thermoelectric Thin Films

Yin

Dun

Gao

et al. 2018

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A systematic colloidal synthesis approach to prepare tin(II, IV) chalcogenide nanocrystals with controllable valence and morphology is reported, and the preparation of solution-processed nanostructured thermoelectric thin films from them is then demonstrated. Triangular SnS nanoplates with a recently-reported π-cubic structure, SnSe with various shapes (nanostars and both rectangular and hexagonal nanoplates), SnTe nanorods, and previously reported Sn(IV) chalcogenides, are obtained using different combinations of solvents and ligands with an Sn precursor. These unique nanostructures and the lattice defects associated with their Sn-rich composition allow the production of flexible thin films with competitive thermoelectric performance, exhibiting room temperature Seebeck coefficients of 115, 81, and 153 μV K for SnS, SnSe, and SnTe films, respectively. Interestingly, a p-type to n-type transition is observed in SnS and SnSe due to partial anion loss during post-synthesis annealing at 500 °C. A maximum figure of merit (ZT) value of 0.183 is achieved for an SnTe thin film at 500 K, exceeding ZT values from previous reports on SnTe at this temperature. Thus, a general strategy to prepare tin(II) chalcogenide nanocrystals is provided, and their potential for use in high-performance flexible thin film thermoelectric generators is demonstrated.

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Enhancement of the thermoelectric performance of bulk SnTe alloys via the synergistic effect of band structure modification and chemical bond softening

Abstract: Seebeck coefficient of SnTe is largely enhanced by large band effective mass or decrease of energy separation through synergistic effect including resonance level and band convergence.

Cited by 69 publications

References 56 publications

Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

CdTe:Sn thin films deposited by the simultaneous laser ablation of CdTe and Sn targets

Controllable Colloidal Synthesis of Tin(II) Chalcogenide Nanocrystals and Their Solution‐Processed Flexible Thermoelectric Thin Films

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