Rectifying characteristics of heterostructures with diamond and diamond-like carbon films

Semiconducting diamond-like carbon (DLC) films were deposited on n-type Si substrates by the electrodeposition method, and diamond films were formed on the carbon film and/or a Si substrate directly by the hot-filament chemical vapor deposition method. Rectifying heterostructures of Al/DLC/Si/Al, AL/diamond/Si/Al, and Al/diamond/DLC/Si/Al were fabricated. The Al/DLC/Si/Al structure has a bulk resistivity of 6 x 10(5) Ohm-cm and a rectification ratio close to two orders of magnitude. Experimental results demonstrate that the Al/diamond/DLC/Si/Al bilayer structure can significantly reduce the leakage current to about 10(-10) A and increase the rectification ratio by 3-5 orders of magnitude at 5 V, compared with that of the other two structures. Possible reasons are given for the changes of the rectifying characteristic.