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.