A strategy for wafer-scale crystalline MoS2 thin films with controlled morphology using pulsed metal-organic chemical vapor deposition at low temperature

Abstract

2D semiconductor materials with layered crystal structures have attracted great interest as promising candidates for electronic, optoelectronic, and sensor applications due to their unique and superior characteristics. However, a large-area synthesis process for various applications and practical mass production is still lacking. In particular, there is a limitation in that a high process temperature and a very long process time are required to deposit a crystallized 2D material on a large area. Herein, pulsed metal-organic chemical vapor deposition (p-MOCVD) is proposed for the growth of wafer-scale crystalline MoS2 thin films to overcome the existing limitations. In the p-MOCVD process, precursors are repeatedly injected at regular intervals to enhance the migration of precursors on the surface. As a result, crystalline MoS2 is successfully synthesized at the lowest temperature (350 degrees C) reported so far in a very short process time of 550 s. In addition, it is found that the horizontal and vertical growth modes of MoS2 can be effectively controlled by adjusting key process parameters. Finally, various applications are presented by demonstrating the photodetector (detectivity = 18.1 x 10(6) at light power of 1 mW) and chemical sensor (response = 38% at 100 ppm of NO2 gas) devices.