LITHIUM FIELD DESORPTION MICROSCOPE - A NEW TOOL FOR SURFACE INVESTIGATIONS

A new method of imaging a surface with field-desorbed metal (Li+) ions is reported. The long-lasting supply of the imaging substance (Li) is achieved by surface diffusion of Li from a multilayer of Li deposited on the shank of the tip. The surfaces of [110]-oriented W and [111]-o riented Rh tips were imaged in continuous, pulsed and mixed continuous -pulsed field modes. Different types of images, formed by ions field-d esorbed from di- or triatomic Li layers on the surface, were observed. The mechanisms of image formation in the lithium field desorption mic roscope (FDM) are discussed on the basis of known properties of field desorption and surface diffusion of Li in comparison with experimental data. The perspectives and possible applications of Li FD for surface investigations are outlined.