Observation of cooper oxide film destruction process by applied DC voltage and current measured by nonlinear distortion methods

Inhalt:
Nonlinear distortion between gold wire and copper surface are studied for the copper oxide destructing process. A copper electrode, oriented (100) single crystal, is used. A copper surface is oxide naturally and oxide forcibly on the hot plate at 220?. Dual frequency method is employed as nonlinear distortion measurement system. The oxide film destruction is performed by applied DC voltage generator to increase up to 2A gradually. A result show that a V letter type valley of the 2nd order distortion voltage, which means the minimum point depends on existence of a contact potential difference. The valley has a tendency to move from plus DC voltage to minus DC one with destruction process before film destruction and after. There is a bright ring (clean copper surface) about 50 to 80 µm diameter after DC current reaches 4A, therefore current constriction mark suggests the current constrict the outer side of the contact area.