Use this URL to cite or link to this record in EThOS:
Title: The development and implementation of variable tip-sample separation scanning tunnelling spectroscopy to enhance spectroscopic measurements
Author: Franks, J. R.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2004
Availability of Full Text:
Access from EThOS:
Scanning Tunnelling Microscopy (STM) and Spectroscopy (STS) are valuable surface science techniques used in the characterisation of a wide variety of surfaces on the atomic scale. When STM and STS are performed concurrently, both the topological and electronic properties of a surface can be investigated. Conventionally, STS is performed with the tip-sample separation fixed, which leads to a limited dynamic range in the measurement. This limitation can be overcome by varying the tip-sample separation during STS. Varying the tip-sample separation improves the dynamic range by exploiting the exponential relationship between tunnel current and tip-sample separation. Instrumentation was designed and fabricated to implement variable tip-sample separation STS with Omicron Scanning Tunnelling Microscopes. To compare variable and fixed tip-sample separation STS, measurements were performed on Si(111) 7x7 and GaAs(110). Normalised conductivity spectra obtained from both material surfaces show improvements in dynamic range and signal-to-noise ratio.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available