Insights on CaTiS3 films grown by pulsed laser deposition

We attempt to grow perovskite CaTiS3 by pulsed laser deposition (PLD) on various substrates using a CaS:TiS2 target. Using Al2O3 (0001) substrates at 600 degrees C deposition temperature in vacuum, Ca1.0Ti1.05S2.48Oy stoichiometry is measured by Energy-dispersive X-ray spectroscopy (EDS) and Ca1.0Ti1.0S2.0O0.7 by Rutherford Backscattering Spectrometry (RBS). This indicates that when the films are grown in vacuum at moderate temperature, a high amount of S can be transferred from the target to the film. While no phase segregation of CaS and TiS2 could be observed, no perovskite CaTiS3 phase could be obtained, but rather a phase governed by van der Waals interactions. The films show a highly doped n-type semiconductor behavior with absorption coefficient in the 105 cm-1 range at 350-2500 nm but no surface photovoltage signal. This work should stimulate further experimental efforts in PLD growth of chalcogenides and chalcogenide perovskites.

Automated summary

We attempted to grow perovskite CaTiS3 using pulsed laser deposition (PLD) on various substrates with a CaS:TiS2 target. The results showed the transfer of sulfur from the target to the film when grown in vacuum at moderate temperature. However, the desired CaTiS3 phase could not be obtained, suggesting a phase governed by van der Waals interactions. The films exhibited highly doped n-type semiconductor behavior without a surface photovoltage signal. This work should inspire further experimental efforts in PLD growth of chalcogenides and chalcogenide perovskites.