Quantum confinement was found to play a critical role in the formation of Au(111) islands grown on the surface of MoS 2 . These confinement effects are fully three dimensional, with a strong correlation to the relatively large Fermi wavelength associated with the Au(111) planes.The confinement effects result in preferred heights with a periodicity of nearly 2 nm and persist to much higher temperatures than are typically seen in electronic growth mode systems. These findings indicate the potential to explore electronic growth modes in a new class of systems based on metal -layered semiconductor interfaces.

Ultrasonic agitation is a proven method for breaking down layered materials such as MoS 2 into single or few layer nanoparticles. In this experiment, MoS 2 powder is sonicated in isopropanol for an extended period of time in an attempt to create particles of the smallest possible size. As expected, the process yielded a significant quantity of nanoscale MoS 2 in the form of finite layer sheets with lateral dimensions as small as a few tens of nanometers. Although no evidence was found to indicate a larger the longer sonication times resulted in a significant increase in yield of single layer MoS 2 , the increased sonication did result in the formation of several types of carbon allotropes in addition to the sheets of MoS 2 . These carbon structures appear to originate from the breakdown of the isopropanol and consist of finite layer graphite platelets as well as a large number of multi-walled fullerenes, also known as carbon onions. Both the finite layer graphite and MoS 2 nanoplatelets were both found to be heavily decorated with carbon onions. However, isolated clusters of carbon onions could also be found. Our results show that liquid exfoliation of MoS 2 is not only useful for forming finite layer MoS 2 , but also creating carbon onions at room temperature as well.

Ballistic electron emission microscopy (BEEM) has been used to study the processes affecting electron transport along the [0001] direction of finite layer MoS2 flakes deposited onto the surface of Au/Si(001) Schottky diodes. Prominent features present in the differential spectra from the MoS2 flakes are consistent with the density of states of finite layer MoS2 calculated using density functional theory. The ability to observe the electronic structure of the MoS2 appears to be due to the relatively smooth density of states of Si in this energy range and a substantial amount of elastic or quasi-elastic scattering along the MoS2/Au/Si(001) path. Demonstration of these measurements using BEEM suggests that this technique could potentially be used to study electron transport through van der Waals heterostructures, with applications in a number of electronic devices.

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