Enhanced thermoelectric performance of SnSe by controlled vacancy population

Ji-Eun Lee; Kyoo Kim; Van Quang Nguyen; Jinwoong Hwang; Jonathan D Denlinger; Byung Il Min; Sunglae Cho; Hyejin Ryu; Choongyu Hwang; Sung-Kwan Mo

doi:10.1186/s40580-023-00381-7

Enhanced thermoelectric performance of SnSe by controlled vacancy population

Nano Converg. 2023 Jul 7;10(1):32. doi: 10.1186/s40580-023-00381-7.

Authors

Ji-Eun Lee^{1

2

3

4}, Kyoo Kim^{2

5

6}, Van Quang Nguyen⁷, Jinwoong Hwang^{1

4

8}, Jonathan D Denlinger¹, Byung Il Min⁶, Sunglae Cho⁷, Hyejin Ryu^{9

10

11}, Choongyu Hwang¹², Sung-Kwan Mo¹³

Affiliations

¹ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
² Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials, Max Plank POSTECH/Korea Research Initiative (MPK), Gyeongbuk, 37673, South Korea.
³ Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea.
⁴ Department of Physics, Pusan National University, Busan, 46241, South Korea.
⁵ Korea Atomic Energy Research Institute, Daejeon, 34057, South Korea.
⁶ Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
⁷ Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan, Ulsan, 44610, South Korea.
⁸ Department of Physics, Kangwon National University, Chuncheon, 24341, South Korea.
⁹ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. hryu@kist.re.kr.
¹⁰ Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials, Max Plank POSTECH/Korea Research Initiative (MPK), Gyeongbuk, 37673, South Korea. hryu@kist.re.kr.
¹¹ Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea. hryu@kist.re.kr.
¹² Department of Physics, Pusan National University, Busan, 46241, South Korea. ckhwang@pusan.ac.kr.
¹³ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. skmo@lbl.gov.

Abstract

The thermoelectric performance of SnSe strongly depends on its low-energy electron band structure that provides high density of states in a narrow energy window due to the multi-valley valence band maximum (VBM). Angle-resolved photoemission spectroscopy measurements, in conjunction with first-principles calculations, reveal that the binding energy of the VBM of SnSe is tuned by the population of Sn vacancy, which is determined by the cooling rate during the sample growth. The VBM shift follows precisely the behavior of the thermoelectric power factor, while the effective mass is barely modified upon changing the population of Sn vacancies. These findings indicate that the low-energy electron band structure is closely correlated with the high thermoelectric performance of hole-doped SnSe, providing a viable route toward engineering the intrinsic defect-induced thermoelectric performance via the sample growth condition without an additional ex-situ process.

Keywords: Defect engineering; Electron band structure; SnSe; Thermoelectric; Vacancy.

Abstract

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