1
|
Hatayama S, Mori S, Saito Y, Fons PJ, Shuang Y, Sutou Y. Nonvolatile Isomorphic Valence Transition in SmTe Films. ACS NANO 2024; 18:2972-2981. [PMID: 38228321 PMCID: PMC10832057 DOI: 10.1021/acsnano.3c07960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 01/18/2024]
Abstract
The burgeoning field of optoelectronic devices necessitates a mechanism that gives rise to a large contrast in the electrical and optical properties. A SmTe film with a NaCl-type structure demonstrates significant differences in resistivity (over 105) and band gap (approximately 1.45 eV) between as-deposited and annealed films, even in the absence of a structural transition. The change in the electronic structure and accompanying physical properties is attributed to a rigid-band shift triggered by a valence transition (VT) between Sm2+ and Sm3+. The stress field within the SmTe film appears closely tied to the mixed valence state of Sm, suggesting that stress is a driving force in this VT. By mixing the valence states, the formation energy of the low-resistive state decreases, providing nonvolatility. Moreover, the valence state of Sm can be regulated through annealing and device-operation processes, such as applying voltage and current pulses. This investigation introduces an approach to developing semiconductor materials for optoelectrical applications.
Collapse
Affiliation(s)
- Shogo Hatayama
- Department
of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11, Aoba-yama, Aoba-ku, Sendai 980-8579, Japan
- Device
Technology Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba 305-8568, Japan
| | - Shunsuke Mori
- Department
of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11, Aoba-yama, Aoba-ku, Sendai 980-8579, Japan
| | - Yuta Saito
- Device
Technology Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba 305-8568, Japan
| | - Paul J. Fons
- Device
Technology Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba 305-8568, Japan
- Department
of Electronics and Electrical Engineering, Faculty of Science and
Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Yi Shuang
- WPI
Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Yuji Sutou
- Department
of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11, Aoba-yama, Aoba-ku, Sendai 980-8579, Japan
- WPI
Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| |
Collapse
|