Angle-resolved X-ray photoelectron spectroscopy of in situ deposited Li on MoS{sub 2}(0002)
A contrasting behavior in alkali/MoS{sub 2} composites is demonstrated between a reductive reconstruction in the Li/MoS{sub 2} system and previously reported pure electron transfer in Cs/MoS{sub 2}. The interaction of in situ cleaved 2H-MoS{sub 2}(0002) with Li was investigated using angle-resolved X-ray photoelectron spectroscopy (ARXPS). The high-resolution XPS in the core level regions revealed that the deposited Li reduced MoS{sub 2}(0002) into Li{sub 2}S/mo(II)S via the reaction 2Li + MoS{sub 2} {r_arrow} Li{sub 2}S + MoS, evidenced by the binding energies and the stoichiometry of Mo, S, and Li. The ARXPS data of the Li 1s, Mo 3d, and S 2p core levels further indicated that the deposited Li together with the reduced MoS{sub 2} surface formed a highly disordered surface region, which extended approximately 12 {angstrom} deep into the MoS{sub 2} bulk. The valence band XPS also revealed a clearly different interaction of Li with MoS{sub 2} from that of Cs. The supravalence electron density of states in Li/MoS{sub 2} appeared at ca. 0.3 eV above the MoS{sub 2} valence band maximum (VBM), whereas that from Cs/MoS{sub 2} was previously observed at 1.25 eV above the VBM, very close to the conduction band minimum of MoS{sub 2}. Thus, the interaction of Li with MoS{sub 2} cannot be characterized by a rigid band model unlike that which made a good approximation for the Cs/MoS{sub 2} system. The Li/MoS{sub 2} specimens were also exposed to molecular oxygen, and the formation of surface peroxide is reported herein.
- Research Organization:
- Baylor Univ., Waco, TX (US)
- Sponsoring Organization:
- US Department of Energy
- DOE Contract Number:
- FG02-86ER13580
- OSTI ID:
- 20034438
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 14 Vol. 104; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
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