Gas-phase synthesis of MoO3 nanoclusters with helium-induced high energy (060) crystal facet: Enhancing oxygen adsorption for improved gas-sensing

Abstract

Adsorbed oxygen species on the surface of metal oxide semiconductors (MOS) play an important role in the field of gas-sensing. However, considering the large number of possible MOS, manipulating surface oxygen species by exposing high-energy crystal facets often requires strict experimental conditions and may not be efficiently repeated for nano MOS. This poses a huge challenge to the rational design of advanced gas-sensing materials. This study explores the fabrication of MoO3 nanocluster (NC) film by cluster beam deposition. Helium (He) is co-fed with argon (Ar) into the aggregation chamber to influence the nucleation and growth of Mo NCs. This unique process facilitated the exposure of the high-energy (060) crystal facet in MoO3 during the aging phase. This exposed crystal facet greatly reduces the oxygen adsorption energy barrier and increases the adsorbed oxygen content, resulting in a significant improvement in gas-sensing performance. The study examined the impact of energetic facets on gas sensor sensitivity by using ethanol, ammonia, and toluene as target gases. The results indicate that exposing high-energy crystal facets significantly enhances sensor performance. This approach to creating NCs with high-energy crystal facets has broad potential for advancing MOS nanostructure-based gas sensors.