Zhen Congmian

Au/Ti/p-Diamond Ohmic Contacts Prepared by Radio-Frequency Sputtering

The as-deposited Au/Ti/p-diamond contacts prepared by rf sputtering are ohmic. The ohmic characteristics of the contacts are improved after annealing. As for the as-deposited and annealed contacts, the specific contact resistivities of 2.886 ? 10-3 and 2.040 ? 10-4 ??cm2 are obtained, respectively. The x-ray photoelectron spectroscopy analysis indicates that the titanium carbide formation occurs at the interface between titanium and the diamond substrate in the as-deposited state, and no TiO2 is observed.

Room-temperature ferromagnetism observed in Si-Al 2 O 3 composite film

Room-temperature ferromagnetism (FM) is observed in Si-Al 2 O 3 amorphous composite film. The magnetic moment is the highest in the case of the Si-Al 2 O 3 composite films with the Si content being 15 vol.%, and distinct domains are detected in our films. The difference in magnetism property between sample annealed in Ar atmosphere and untreated composite film indicates that the observed ferromagnetism does not originate primarily from oxygen defects. It is concluded that the ferromagnetism arises from the direct coupling between defects. These defects orignate from the interface between Si particles and Al 2 O 3 matrix. By varying the Si content in the film, one can change the defect density and thereby control the strength of the ferromagnetic coupling.