Atmospheric Pressure CVD of TiSe2 Thin Films on Glass

Atmospheric pressure (AP) CVD of TiSe2 films on glass substrates was achieved by reaction of di‐tert‐butylselenide and diethyl diselenide with TiCl4 at 250–600 °C. All the films showed a TiSe2 Raman pattern with bands at 133 cm–1 and 198 cm–1. X‐ray diffraction (XRD) showed that the TiSe2 films were crystalline with cell constants close to those expected: some preferred orientation was noted at higher deposition temperatures. Energy dispersive analysis by X‐rays (EDAX) gave a Ti:Se ratio close to 1:2 for all the films formed at 550 °C, and a Ti:Se ratio close to 1:1.5 for the film formed at 600 °C. The TiSe2 films produced from diethyl diselenide and TiCl4 had a powdery, purple, matte appearance whilst reaction with di‐tert‐butylselenide formed navy‐blue reflective films at deposition temperatures below 300 °C, and dark‐purple films at deposition temperatures above 350 °C. Scanning electron microscopy (SEM) showed that the films were composed of needle‐like crystals which became longer and thicker with increasing deposition temperature. After 60 days storage in air, Raman spectra of the films produced from diethyl diselenide and TiCl4 revealed the presence of TiO2, whereas no change was noticed in the XRD and Raman spectra of the films produced from di‐tert‐butylselenide and TiCl4. Atmospheric pressure chemical vapor deposition (APCVD) of TiSe2 films (see Figure) on glass substrates was achieved by reaction of di‐tert‐butylselenide and diethyl diselenide with TiCl4 at 250–600 °C. The films were either navy blue or bronze in color depending on conditions.