Spin deposition of MoS x thin films

Autor: Michel A. Aegerter, Jörg Pütz
Rok vydání: 1999
Předmět:
Zdroj: Thin Solid Films. 351:119-124
ISSN: 0040-6090
DOI: 10.1016/s0040-6090(99)00255-2
Popis: Thin films of MoS 2 and amorphous MoS 3 have been prepared on various glass and stainless steel substrates by thermolysis of spin cast solutions of (NH 4 ) 2 MoS 4 in an organic diamine (ethylenediamine and 1,2-diaminopropane). After deposition the resulting single-source precursor film [(H 3 NC n H 2n NH 3 )MoS 4 ] was dried at 250°C in air and subsequently heat treated at temperatures between 300 and 800°C under inert nitrogen (N 2 ) atmosphere yielding films of MoS x (2 ≤ x ≤ 3) with carbon impurities. The resulting films with thicknesses up to 160 nm (800°C) and 250 nm (300°C) are highly homogeneous with a metallic lustre and appear brown in transmission. While the films are amorphous to X-ray diffraction up to temperatures of 400°C, the crystallinity increases for higher temperatures due to the formation of MoS 2 microcrystallites. Furthermore, the composition and the microstructure strongly depend on the used diamine solvent. Both X-ray and electron diffraction reveal a partially preferred orientation of the crystallites with their basal planes parallel to the substrate ( ⊥ c, type II). After heat treatment at 800°C under N 2 the MoS 2 layer stacks consist of three to four layers with a length of 5-8 nm. The optical characterisation of the thin films shows a strong absorption in the visible part of the spectrum characteristic of MoS 2 with an absorption coefficient α 550 of 2 × 10 5 cm 1 . Tribological measurements up to 5000 cycles against steel reveal the highest wear-life with a friction coefficient μ < 0.1 for coatings heat treated at 500°C. The highest capacity for reversible electrochemical Li intercalation of 30 mC/cm 2 was found in amorphous MoS x coatings (400°C heat treatment). A weak electrochromic effect with a change in transmission of ΔT 0.08 around 800 nm was observed after Li intercalation.
Databáze: OpenAIRE
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