New Characterisation Methods

Vortex electron beams

Vortex electron beams

Professor Yuan’s research group focus on the development of nanoscale characterization techniques and their application to the investigation of nanophysics of advanced materials. Highlights of this is the significant contribution to the quantitative fine structure analysis of the electron energy loss spectroscopy in electronically anisotropic materials such as graphene and metal dichalcogenide used in ultrathin electronics.

Scanning Thermal Microscopy

‌‌Topography image from AFM shows SiO2 thin film is sitting 100 nm above Si substrate.  Thermal image from SThM reveals this SiO2 film is 0.3oC hotter than Si. We are developing a Scanning Thermal Microscope (SThM) at York to study thermal transport at micro- and nano-scale.1,2  SThM is a branch of Atomic Force Microscopy (AFM) where a thermal probe is used in place of a conventional AFM probe. 

Liquid Cell TEM

Liquid cell transmission electron microscopy

A novel sample holder (Protochips Inc.) for transmission electron  microscopy (TEM) allows for the imaging of objects in liquid environments such as minerals forming from supersaturated ionic solutions or biogenic  materials that undergo significant changes when dried or frozen to be imaged in TEM. This versatile technique  gives access to many aspects of liquid phase processes with an unprecedented spatial resolution of less than 1 nm, especially if scanning TEM (STEM) is used for imaging. We are using this technique to study the dynamics of the formation of minerals such as calcium carbonate or hydroxyapatite from solution.