Engineering Scalable Processes and Interfaces for 2D Electronic Devices

Moody, Michael

doi:https://doi.org/10.21985/n2-q901-pz35

Work

Engineering Scalable Processes and Interfaces for 2D Electronic Devices

Public

Download PDF

Download All Files (.zip)

Scalable processing of well-defined interfaces is key not only for wider application of two-dimensional (2D) materials in technology but also for improved fundamental understanding. Atomic layer deposition has useful characteristics, especially self-limited growth at low temperatures, that make it well suited for the production of uniform interfaces. Related processes, such as other pulsed metal-organic chemical vapor deposition (MOCVD) techniques, can preserve some of these beneficial characteristics with additional flexibility in process design. This thesis reports the development of deposition processes for semiconductors, ferroelectrics, and dielectrics. In particular, a low-temperature atomic layer deposition (ALD) process for MoS2 was developed, and the semiconducting properties of films produced via growth and annealing were measured. A growth process for the ferroelectric semiconductor SnS was optimized for the 2D insulator substrate hBN, and epitaxy, mechanical sliding behavior, and electric polarization was characterized. An ALD process for MoOx with adjustable composition was developed, and the growth product was applied as a charge transfer doping dielectric for 2D semiconductors. Finally, the behavior of current injection at metal / 2D semiconductor contacts was studied, and ALD oxide interfacial layers were explored to improve contact behavior. Investigations of these disparate systems highlight both common and distinct challenges in deposition processes that are enabling for 2D electronic devices. In each case, interactions across van der Waals interfaces, while weak compared to covalent or ionic bonding, prove strong enough to markedly influence adjacent materials in ways ranging from charge transfer to epitaxy.

Creator