Carbon-Based Solar Cell from Amorphous Carbon with Nitrogen Incorporation

Abstract

Nitrogen doped amorphous carbon (n-C:N) solar cells were successfully prepared using a simple and low cost Chemical Vapor Deposition (CVD) method using camphor oil as a precursor. Four samples of n-C:N were deposited by varying the deposition temperature (500oC, 550oC, 600oC, 650oC). The fabricated solar cell using n-C:N with the configuration of Au/n-C:N/p-Si/Au achieved an increasing efficiency as temperature increase (0.000202% to 0.001089%). As a reference, pure a-C was deposited at 500oC and exhibit 0.000048% efficiency. The current-voltage (I-V) graph emphasized on the linear graph (ohmic) for the a-C thin films, whereas for the p-n device structure, a rectifying curve was obtained. Electrical conductitivity possesses increasing value (1.69 x 10-2 to 22 Ω-1 cm-1) due to increasing sp2 ratio in a-C as temperature increase. The rectifying curves signify the heterojunction between the n-doped a-C film and the p-Si substrate and designate the generation of electron-hole pair of the samples under illumination. Photoresponse characteristics of the deposited a-C was highlighted when being illuminated (AM 1.5 illumination: 100 mW/cm2, 25oC) and optical band gap for the nitrogen doped a-C is reported from 0.75 eV to 0.25 eV as temperature increase.