Electrical properties of partially nitrided LiCoO₂ thin films with an equivalent amount of Li and Co

ABSTRACT

Partially nitrided LiCoO₂ thin films with stoichiometric contents of Li and Co were fabricated on sapphire substrates using an ethanol solution. The precursor films were formed by spin-coating. By thermal treatment of` the precursor films at 350, 450, 550 and 650°C for 30 min in air, four kinds of LiCoO₂ thin films were obtained. That annealing of the precursor film at 650°C resulted in the nucleation of Co₃O₄ from the layered LiCoO₂, which has been confirmed by the Raman spectrum. Three X-ray photoelectron spectroscopy peaks observed at 527.9 eV, 402.1 eV, and 396.2 eV were newly assigned to the O-Co⁴⁺, N-Co⁴⁺, and N-Co²⁺ bonds, respectively, using a peak-analysis technique. The resistivity of the layered LiCoO₂ thin film fabricated at 650°C was measured to be 1.2 Ω cm.

KEYWORDS:

• Layered LiCoO₂
• resistivity
• X-ray photoelectron spectroscopy
• Hall effect measurement

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Numbers [25410204 and 26810130]; and the JST-Mirai Program, Grant Number [JPMJMI18DA]. This study was also financially supported by the international research project of Kogakuin University in collaboration with the National University of Singapore.