Nanoscale Visualization of the Electrostatic Barrier at a Material Interface Utilizing Scanning Probe Microscopy and Computational Modeling

Electrostatic barriers at material interfaces are the foundation of current and futuristic electronic and optoelectronic devices. Visualization of the electrostatic barrier at an interface can be accomplished with nanoscale resolution utilizing ballistic electron emission microscopy (BEEM), an STM-based technique [1]. A spatial map of the barrier is formed by collecting tens of thousands of BEEM spectra on a regularly spaced grid and fitting them to extract the local barrier height. These maps and histograms that display the frequency of specific barrier energy, provide insight into the physical and chemical composition of the interface as well as the hot electron scattering. Computational modeling of the histograms simulates the distributions of barrier heights and provides quantitative information such as scattering rates and relative presence of different barrier height energies. A discussion of the ultimate spatial and energetic resolution will be presented, along with numerous examples such as incomplete silicide formation, multiple metal species at the interface, and monolayer thick dielectric layers [2,3].

[1] Westly Nolting, Chris Durcan, Steven Gassner, Joshua Goldberg, Robert Balsano, Vincent P. LaBella, Journal of Applied Physics, 123 245302 (2018).

[2] Jack Rogers, Westly Nolting, Chris Durcan, Robert Balsano, Vincent P. LaBella, AIP Advances, 11 025108 (2021).

[3] Jack Rogers, Hyeonseon Choi, Steven Gassner, Westly Nolting, Daniel Pennock, Steven Consiglio, Vincent P. LaBella, Journal of Applied Physics, 126 195302 (2019).