SURFACE MODIFICATION BY THE VOLTAGE PULSE IN A SCANNING TUNNELING MICROSCOPE

Experiments on the study of the modification mechanism of a metal surf ace by a voltage pulse in a scanning tunneling microscope are carried out. The received results shown that the value of a current flowing in a tip-sample circuit plays an important role during nanostructures fo rmation. Measurements of a voltage drop in the tunneling gap at the su rface modifications testify to the formation of a contact between a ti p and sample. The received results are explained on the basis of the m echanism of thermal expansion of the tip apex region. The performed ca lculations of the emission characteristics for a case of a trapezoidal barrier testify to the proposed mechanism. They have shown that the c hange of emission current by a change of a potential difference is not great as for the field emission case. Moreover, the energy released b y Nottingham effect essentially surpasses that released in the field e mission case. (C) 1997 American Vacuum Society.