Self-catalyzed vapor-liquid-solid growth of GaS nanobelt for nano-optoelectronic applications

GaS, with the largest bandgap of group III-VI van der Waals semiconductors, is a potential building block of optoelectronic applications. In addition, one-dimensional structures, such as nanobelts, are preferable for integration into future nano-optoelectronic devices. Here, we demonstrated self-catalyzed vapor-liquid-solid (VLS) growth of a GaS nanobelt by metalorganic chemical vapor deposition. Ga-rich growth conditions caused Ga particles to be generated in the initial growth step. The nanobelt grew from a Ga particle, which acted as a catalyst. The fabricated nanobelt photodetector showed a high ON/OFF ratio and the dark current was under the detection limit. Moreover, compared with an exfoliated GaS flake photodetector, it had one order of magnitude higher responsivity. These outstanding photoresponse properties indicate that self-catalyzed VLS growth of GaS nanobelts is a promising bottom-up integration approach for nano-optoelectronic applications.