Impact of Radiation on the Electronic Structure of MoS2
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Electrons in a semiconductor occupy states within certain energy ranges, called energy bands. The position of the Fermi level with respect to these energy bands determines the charge carrier type of the semiconductor. Molybdenum disulfide (MoS2) is a two-dimensional, n-type semiconductor with potential applications in flexible electronics, transparent electronics, and optoelectronics. Electronic devices containing MoS2 could be used in environments where radiation affects device performance. Thus, it is important to determine the impact of radiation on MoS2. A one-molecule-thick layer of MoS2 (monolayer) and a two-molecule-thick layer of MoS2 (bilayer) were placed onto different areas of a gold (Au) substrate containing 1.2-µm-deep holes. The MoS2 was suspended over these holes but supported by the Au elsewhere on the substrate. This sample configuration was used to determine the effect of He+ radiation on the electronic properties of the suspended MoS2 and the Au-supported MoS2. The MoS2 was irradiated by He+ ions in two stages. The energy bands of the MoS2 were measured with respect to the Fermi level via photoelectron emission microscopy before irradiation and after each irradiation stage. From each measurement, the charge carrier type of the MoS2 after the corresponding irradiation stage was determined. The Fermi levels of the suspended monolayer and bilayer decreased by ≈0.15 eV with respect to the bands during the first irradiation stage During the second irradiation stage, however, the Fermi levels didn’t change significantly. This lack of change supports the existence of a radiation threshold, above which the electronic properties of suspended MoS2 remain the same. The Fermi levels of the supported monolayer and bilayer increased over the cumulative irradiation and didn’t show evidence of a threshold. Thus, suspended MoS2 becomes less n-type as it is irradiated. Supported MoS2, however, becomes more n-type as it is irradiated. These results could inform the development of radiation tolerance standards for MoS2, and thus, radiation-tolerant MoS2-based electronics.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Office of Workforce Development for Teachers & Scientists (WDTS); USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- NA0003525
- OSTI ID:
- 1879807
- Report Number(s):
- SAND2022-10605R; 708876; TRN: US2308748
- Country of Publication:
- United States
- Language:
- English
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