Pulsed Supermagnetron Plasma CVD of a-CN<sub>x</sub>:H Electron-Transport Films for Au/a-CN<sub>x</sub>:H/p-Si Photovoltaic Cells
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Abstract
Hydrogenated amorphous carbon nitride (a-CN<sub>x</sub>:H) films were formed on p-Si wafers set on a lower elec-trode by pulsed supermagnetron plasma CVD using i-C<sub>4</sub>H<sub>10</sub> and N<sub>2</sub> gases. Lower electrode RF power (LORF) of 13.56 MHz (50 - 800 W) was modulated by a 2.5-kHz pulse at a duty ratio of 12.5%, and upper electrode RF power (UPRF) of 50 - 400 W was supplied continuously. The optical band gap decreased with an increase in LORF at each UPRF. The open circuit voltage of Au/a-CN<sub>x</sub>:H/p-Si photovoltaic cells (a-CN<sub>x</sub>:H film thickness: 25 nm) was about 200 mV for each cell, and the short circuit current density and energy conversion efficiency increased with LORF for each UPRF. The highest energy conversion efficiency of 0.81% was obtained at UPRF/LORF of 200/800 W.
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