Nagoya University

Akiko Okano

Ken Hattori

Yasuo Nakai

Noriaki Itom

Junichi Kanasaki

Noriaki Itoh

The ablation threshold of a laser fluence with respect to the surface of a sample manufactured in a high vacuum chamber is determined by using the sample. The quantity of vacancy-type defects is determined by radiating a laser beam having a fluence slightly higher than the ablation threshold on the surface. At the same time, the quantities of adatom-type and kink-type defects are determined by radiating a pulsed laser beam having a fluence slightly lower than the ablation threshold on the surface repeatedly to obtain the relation between an emission yield and the number of laser pulses. The quantity of the adatom-type defects is obtained by determining the area (total quantity of emitted atoms) of a rapidly decreasing portion of the relation. The quantity of kink-type defects is obtained by determining a magnitude of an emission yield of a slowly decreasing portion of the relation.

Method of quantitative determination of defect concentration on surfaces

A basic sample having a surface is set in an ultrahigh vacuum chamber. Atoms constituting the sample are deposited on the surface of the sample to remove vacancy-type defects. A laser beam having a predetermined wavelength and a predetermined fluence is radiated on the sample to remove adatom-type and kink-type defects, thereby producing a defect-free surface. In addition, the same material as that for a basic sample is deposited on a defect-free surface to produce a defect-free thin film.

Growing community of inventors

Toyota, Japan

Akiko Okano