Investigation of compound micro cantilever for imaging and identifying micro/nano particulates

by 1977- Narayanan, Ramanathan

Atomic Force Microscopes (AFM) are typically used to image surfaces along with small particulates that may be deposited on the surface. Surface imaging can be made down to the atomic level but usually it is conducted at the nano and micro scales. It is highly desirable to identify the constituency of particulates on the surface and if possible determine the chemical and physical identity of particulates. The objective of the research presented in this thesis is to establish the feasibility of using dual micro cantilevers to determine the physical constituency of nano particles deposited to the micro surface. The goal at this point is not to determine the physical properties of a particulate but rather to determine whether the particulate is hard or soft and categorize it. The research addresses this goal by predicting the vibration response of dual micro cantilever when the cantilever tip engages a surface and a particulate. Five different particulate models are analyzed: elastic, viscous, visco-elastic in parallel, visco-elastic in series and visco-elastic in series/parallel. Each model represents different possible physical constituencies of particles. The analysis shows that each particle model produces unique signatures and vibration responses of the dual micro cantilever. Properties that are identified in the research are signatures. Signatures can be shifts in natural frequencies, change in response amplitudes and phase angles. iv