Field emission current from Si tip: ultra-fast time resolved measurements

We have carried out time resolved measurements of field emission currents from silicon tips. The ultra-fast spectroscopy has been carried out by a femtosecond field emission camera originally developed to observe single adsorbate dynamics on metal tips. As a preliminary observation of semiconductor surface dynamics, we have performed measurements in picosecond time resolution. Even though the maximum current in the present set-up is not enough to study the single atomic dynamics on silicon surfaces, one can gain information on collective motions of atoms and on electron tunneling from silicon surfaces. The maximum current density achieved in our study is comparable to those reached by solid state tunneling devices.