IVC17 / ICSS13 and ICN+T 2007

Electrical properties of the diamond like carbon films irradiated with high energy photons
Laurikaitiene, Jurgita; Meskinis, Sarunas; Adliene, Diana; Sablinskas, Valdas; Tamulevicius, Sigitas; Kopustinskas, Vitoldas; Sniureviciute, Migle; Mockeviciene, Skirmante; Gudaitis, Rimantas Lithuania

Crystalline diamond and diamond like carbon (DLC) films have been found to be very promising radiation detector materials due to their specific optical, mechanical, and electrical properties in the past decade. Properties of crystalline diamond and polycrystalline DLC films produced using CVD techniques have been investigated in different studies. However there are only a few studies on possible application of amorphous DLC films as the active layers for the detection of ionizing radiation, due to the lack of information about the behaviour and properties of these DLC films after irradiation with high energy photons. The aim of this work was to investigate electrical properties of the amorphous DLC films before and after irradiation with high energy photons with the scope to apply these films in the construction of medical radiation detectors.
SiOx containing DLC films have been synthesized at room temperature by direct ion deposition (cold cathode method) from hexametildisiloxane vapour and hydrogen gas mixture. Produced DLC films were irradiated with high energy photons (1.25 MeV) from medical 60Co source and X-ray photons (6 MV, 10MV and16 MV) generated in medical linear accelerator Clinac (VARIAN). Electrical properties of Al-Si-DLC-Al structures were studied using pikoampermeter KEITHLEY 6487.
The dependence of current-voltage (I-V) characteristics of samples on the energy of X-ray photons and X-ray irradiation dose has been investigated. Breakdown strength, leakage current and dielectric permittivity of the diamond like carbon films were measured before and after the irradiation. Mechanisms of the X-ray irradiation introduced changes of the electrical properties of the amorphous DLC films are discussed on the basis of the obtained results.

back