The Cu<sub>2</sub>O thin films were synthesized by using RF sputtering technique. Comparisons were made with films created by deposition at room temperature followed by thermal annealing between 100°C...The Cu<sub>2</sub>O thin films were synthesized by using RF sputtering technique. Comparisons were made with films created by deposition at room temperature followed by thermal annealing between 100°C and 400°C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. The thickness of the thin films was kept constant, around 2000 <span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span> (Angstrom). In addition, the RF power and pressure deposition were kept constant, as well. The thin films were evaluated for a range of wavelengths between 200 nm and 400 nm (Ultra Violet spectrum), 400 nm and 700 nm (Visible spectrum), 700 nm and 800 nm (Infrared spectrum) for both, optical transmittance and photoluminescence. From the experimental results, the higher annealing temperature and the introduction of nitrogen (N<sub>2</sub>) gas produced the following results: the optical bandgap for the Cu<sub>2</sub>O was found to be 2.23 eV and photoluminescence peaks were around 551 nm and 555 nm, which matched the theoretical analyses. Overall, there was a decrease in the optical bandgap of the Cu<sub>2</sub>O from 2.56 eV at room temperature to 2.23 eV for the film annealed in nitrogen gas at 400°C. This indicates that the Cu<sub>2</sub>O is a potential candidate in solar cell applications.展开更多
Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available,...Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available, we must research alternative materials such as copper oxides. Some benefits of copper oxides include being available in abundance, affordable, low toxicity, low bandgap, and a high absorption coefficient—all of which contribute to it being a valuable interest for the manufacturing of solar cells. In this study, CuO thin films were synthesized utilizing RF sputtering technique with deposition occurring at room temperature followed by thermal annealing between 100°C and 400<span style="white-space:normal;">°</span>C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. Afterwards, these thin films were evaluated for a range of wavelengths: 200 - 400 nm (UV spectrum), 400 - 700 nm (Visible spectrum), and 700 - 800 nm (IR spectrum), for both, optical transmittance and photoluminescence. In addition, the CuO results were compared to our Cu<sub>2</sub>O results from a previous study to assess their differences. In the results of this study, the CuO thin film initially had a bandgap of 2.19 eV at room temperature, and by increasing the annealing temperature to different levels, the bandgap decreased respectively. The presence of air in the chamber allowed for the highest decrease, followed by the nitrogen (N<sub>2</sub>) and the lowest decrease was observed in the presence of oxygen (O<sub>2</sub>). This was reflected in the decrease in the bandgap values from 2.19 eV (room temperature) to 2.05 eV for the films annealed at 400<span style="white-space:normal;">°</span>C.展开更多
文摘The Cu<sub>2</sub>O thin films were synthesized by using RF sputtering technique. Comparisons were made with films created by deposition at room temperature followed by thermal annealing between 100°C and 400°C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. The thickness of the thin films was kept constant, around 2000 <span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span> (Angstrom). In addition, the RF power and pressure deposition were kept constant, as well. The thin films were evaluated for a range of wavelengths between 200 nm and 400 nm (Ultra Violet spectrum), 400 nm and 700 nm (Visible spectrum), 700 nm and 800 nm (Infrared spectrum) for both, optical transmittance and photoluminescence. From the experimental results, the higher annealing temperature and the introduction of nitrogen (N<sub>2</sub>) gas produced the following results: the optical bandgap for the Cu<sub>2</sub>O was found to be 2.23 eV and photoluminescence peaks were around 551 nm and 555 nm, which matched the theoretical analyses. Overall, there was a decrease in the optical bandgap of the Cu<sub>2</sub>O from 2.56 eV at room temperature to 2.23 eV for the film annealed in nitrogen gas at 400°C. This indicates that the Cu<sub>2</sub>O is a potential candidate in solar cell applications.
文摘Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available, we must research alternative materials such as copper oxides. Some benefits of copper oxides include being available in abundance, affordable, low toxicity, low bandgap, and a high absorption coefficient—all of which contribute to it being a valuable interest for the manufacturing of solar cells. In this study, CuO thin films were synthesized utilizing RF sputtering technique with deposition occurring at room temperature followed by thermal annealing between 100°C and 400<span style="white-space:normal;">°</span>C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. Afterwards, these thin films were evaluated for a range of wavelengths: 200 - 400 nm (UV spectrum), 400 - 700 nm (Visible spectrum), and 700 - 800 nm (IR spectrum), for both, optical transmittance and photoluminescence. In addition, the CuO results were compared to our Cu<sub>2</sub>O results from a previous study to assess their differences. In the results of this study, the CuO thin film initially had a bandgap of 2.19 eV at room temperature, and by increasing the annealing temperature to different levels, the bandgap decreased respectively. The presence of air in the chamber allowed for the highest decrease, followed by the nitrogen (N<sub>2</sub>) and the lowest decrease was observed in the presence of oxygen (O<sub>2</sub>). This was reflected in the decrease in the bandgap values from 2.19 eV (room temperature) to 2.05 eV for the films annealed at 400<span style="white-space:normal;">°</span>C.
