Controlled growth and transport property of Bi₂Se₃ and WSe₂ thin film

In this work, we prepared a high-quality topological insulator (TI) and transition metal dichalcogenide (TMD) thin films by magnetron sputtering. Single-target sputtering and co-sputtering techniques are used to prepare these samples. Bi₂Se₃ and WSe₂ were fabricated by radiofrequency magnetron sputtering at temperature T = 300K – 450K, and their properties were evaluated. Bi₂Se₃ (x) and WSe₂ thin films with different compositions (x=5, 25, 50, 100, and 125) on sapphire were fabricated. For selenium (Se) deficiency, Se was co-sputtered with composite TI and TMD targets. Rapid temperature annealing was done to crystallize the film. The prepared thin film's XRD, XPS, and Raman measurements were conclusive. To perform the transport measurements millimeter size Hall-bar device is fabricated using a mask, not by using lithography and resist. The transport measurements have been done at different temperatures from T = 4 - 300K. For TI (Bi₂Se₃), the magnetoresistance is linear with the field. We reported finding high conductivity for Bi₂Se₃, which implies surface conductivity. For TMD (WSe₂), we reported having semiconducting conductivity.