Pulsed laser deposition of highly c-axis oriented thin films of BSTS topological insulator.

We report the growth of highly c-axis oriented topological insulator (TI) BiSbTe1.5Se1.5 (BSTS) thin films by pulsed laser deposition (PLD) technique. The various growth parameters such as substrate temperature, Argon pressure in the deposition chamber and target to substrate distance are tuned to obtain the optimized conditions essential for stoichiometric and bulk insulating TI thin films. These films are highly c-axis oriented and exhibit all the four Raman modes characteristic to the R-3m space group. The quality of the deposited thin films is investigated using X-ray diffraction for crystallinity, Raman spectroscopy for lattice dynamics, morphological studies using scanning electron microscope and compositional analysis using Energy dispersive X-ray spectroscopy. Resistance vs temperature measurements confirm bulk insulating nature of the prepared thin films and magnetoresistance data exhibits the phenomena of weak antilocalization with a large phase coherence length.