Controlling Properties of Few-Layer MoS_2 with a Multi-Laser Process Scheme

摘要

Molybdenum disulfide (MoS_2) films have attracted a great deal of research interest due to the unique properties of films when the thickness is a few atomic layers: Previous work in the literature has shown high field-effect mobility (comparable to graphene), and a large direct bandgap (around 1.8 eV), along with a high strain limit (~10%). We demonstrate a complex multi-laser process scheme based on a direct-write system - comprised of co-incident pulsed and CW lasers where each laser amplitude is modulated to a predefined script for precise control of laser doses. The arrangement enables tuning the properties of a sputtered MoS_2 thin film. We focus on properties which are expected to be of use in flexible electronics and chemical sensing device applications. First, we demonstrate the process for inducing crystallinity from the amorphous phase and reducing the layer thickness down to the regime of several monolayers. Second, we measure electrical conductivity using both pure sputtered MoS_2 films and films co-sputtered with small amount of gold (<20%). Third, we measure the wettability of the processed surface, as measured by droplet contact angle. The measurements compare the properties under different processing conditions.