Electrical characterization of nanocrystalline Si films by scanning tunnelling spectroscopy and beam-induced current in the scanning tunnelling microscope

Abstract

Nanocrystalline silicon films, with an average nanocrystal size of about 10 nm, obtained by boron implantation of amorphous silicon layers, have been studied by remote-beam-induced current (REBIC) in a scanning tunnelling microscope (STM) and by current imaging tunnelling spectroscopy. STM images reveal a cell structure with cell sizes of about 200 nm. STM-REBIC images display space-charge regions associated with the cell boundaries. The STM-REBIC contrast has been found to depend on the implantation dose and the thermal treatment given to the sample. The results show the capability of STM-REBIC to image electrically active regions in nanocrystalline silicon films with a resolution of up to 10 nm.