Spectral Photoresponse of Nitrogen Incorporated Carbon Thin Films

The spectral photoresponse of nitrogen doped n-type amorphous carbon (n-C:N) films obtained from camphoric carbon (C₁₀H₁₆O) target on single crystal Si (100) substrate at room temperature is investigated. Photoresponse analyses of the films were done, with different nitrogen partial pressures (NPP) in the range from 0.3 to 50 mTorr, using curve fitting technique. Photoresponse of the films was maximum at 1 mTorr NPP. The total photoresponse of the film varies in similar pattern to that of the carbon contribution. Si contribution remains constant from 0.4 to 10 mTorr and gradually increases from 10 to 50 mTorr. Above 10 mTorr there is trend of graphitization with increased sp² hybridization and reduced sp³ hybridization. Sp² contribution was more than 50 percent on all the cases of NPP doping. The variation of relative C and Si contributions is inversely proportional to each other.