Electrical Properties and Thermal Annealing Effects of Polycrystalline MoS2-MoSX Nanowalls Grown by Sputtering Deposition Method

Straightforward growth of nanostructured low-bandgap materials is a key issue in mass production for electronic device applications. We report here facile nanowall growth of MoS2-MoSX using sputter deposition and investigate the electronic properties of the nanowalls. MoS2-MoSX nanowalls become gradually thicker and taller, with primarily (100)-plane growth directions, with increasing deposition time. Nanowalls combine with nearby walls when a rapid thermal annealing (RTA, 200 degrees C-500 degrees C) process is applied. All samples have conventional low-bandgap semiconductor behavior with exponential resistance increase as measurement temperature decreases. The 750 nm-thick MoS2-MoSX nanowalls have a sheet carrier mobility of up to 2 cm(2)center dot V-1 center dot s(-1) and bulk carrier concentration of similar to 10(17)-10(19) cm(-3) range depending on RTA temperature. Furthermore, perpendicular field-dependent magnetoresistance at 300 K shows negative magnetoresistance behavior, which displays resistance decay by applying a magnetic field (MR ratio in the -1 % range at 5 T). Interestingly, 400 degrees C RTA treated samples show a resistance upturn when applying an external magnetic field of more than 3 T. Our research suggests tuneability of MoS2 nanowall size and mesoscopic electronic transport properties.