Routine Defect Characterization and Creation of Single Photon Emitters in Two-Dimensional Materials with Atomic Force Microscopy

When and Where

Nov 30, 2023
3:45pm - 4:15pm

Hynes, Level 3, Room 309

Presenter

Matthew Rosenberger

Co-Author(s)

Matthew Rosenberger¹

University of Notre Dame¹

Abstract

Matthew Rosenberger¹

University of Notre Dame¹

Two-dimensional materials (2DM) are atomically thin materials with extraordinary mechanical, electrical, and chemical properties that make them promising for next generation technologies in quantum communications, sensing, flexible and transparent electronics and optoelectronics, and energy conversion. The behavior of these materials depends on nanoscale details, such as intrinsic point defects and strain fields. In this talk, I will discuss the use of atomic force microscopy (AFM) for characterizing and manipulating 2DM at the nanoscale. First, I will describe our recent work on developing AFM-based techniques for rapid and routine point defect quantification in transition metal dichalcogenides (TMDs). Through direct comparison of conductive AFM and scanning tunneling microscopy (STM), we show that conductive AFM identifies the same defects as STM, validating conductive AFM as a standard defect quantification technique. I will also demonstrate that lateral force microscopy (LFM) can visualize point defects in both TMDs and hexagonal boron nitride. Since LFM is a mechanical technique, it does not require a conductive pathway, which is a significant advantage compared to conductive AFM and STM. In the second part of this talk, I will discuss our work on using AFM tips to write strain profiles into TMDs with nanometer-scale precision. Briefly, we use the AFM tip to indent 2DM placed on top of a thin polymer layer, which results in strain texturing. We use this technique to deterministically place single photon emitters (SPEs) in WSe2. We find that electrical gating can improve the purity of SPEs created with this method. M. Rosenberger et al., ACS Nano, 2018, 12 (2), 1793-1800 (DOI: 10.1021/acsnano.7b08566) M. Rosenberger et al., ACS Nano, 2019, 13 (1), 904-912 (DOI: 10.1021/acsnano.8b08730) K. McCreary et al., ACS App. Mat. and Int., 2020, 12 (8), 9580-9588 (DOI: 10.1021/acsami.9b19561) C. Stevens et al., ACS Nano, 2022, 16 (12), 20956-20963 (DOI: 10.1021/acsnano.2c08553)