Study of field-emitting microstructures using a scanning tunneling microscope
- Departement de Physique de la Matiere Condensee, Universite de Geneve, CH-1211 Geneve, Switzerland (CH)
Field emission from broad metal cathodes is known to be strongly enhanced at a small number of emitting sites per cm{sup 2} compared to the expected Fowler--Nordheim emission from ideal, flat surfaces. We have operated a scanning tunneling microscope (STM) in the field emission regime (typical tip voltage: +80 V) and measured the local field emission strengths and variations on niobium samples. With a modulation technique, which is an adaptation of the standard work function measurement, maps of the field enhancement factor {beta} have been obtained. An example of an emission site is presented where STM topograph and {beta} map are compared with a secondary electron microscope image and with field emission data obtained in a standard way using high-voltage anodes. This demonstrates the capability of a scanning tunneling microscope to localize enhanced field emission sites (with typical {beta} values of 50 in the present work) with high spatial resolution and to study surfaces down to the limit {beta}=1.
- OSTI ID:
- 7247169
- Journal Information:
- Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Vol. 8:1; ISSN 0734-2101
- Country of Publication:
- United States
- Language:
- English
Similar Records
DC Scanning Field Emission Microscope Integrated with Existing Scanning Electron Microscope
Direct current scanning field emission microscope integrated with existing scanning electron microscope