Low-temperature grown vertically aligned carbon nanotube array for an optimal infrared bolometer

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Vertically aligned carbon nanotube (VACNT) arrays are investigated as absorbers for thermal-type photodetectors.
• Optimizing VACNT properties like height, density, and growth temperature is crucial for balancing high absorption rates with fast response speeds, essential for effective photodetector performance.

Purpose of the Study:

• To optimize VACNT arrays for thermal photodetectors by achieving a balance between high absorption and fast response speed.
• To develop a low-temperature fabrication process for VACNTs suitable for integration with sensitive photodetector materials.

Main Methods:

• Fabrication of VACNT arrays with varying heights and densities using a low-temperature plasma-enhanced chemical vapor deposition (PECVD) process.
• Measurement of absorption coefficients using Fourier transform infrared (FTIR) spectroscopy.
• Development and application of an effective medium theory (EMT) model to theoretically analyze VACNT absorption properties.

Main Results:

• VACNT arrays were successfully prepared with controlled heights and densities via low-temperature PECVD.
• Experimental absorption coefficients were measured and found to be comparable to theoretical values predicted by the EMT model using extracted CNT parameters.
• The study demonstrates a viable method for optimizing VACNT absorbers for photodetector applications.

Conclusions:

• Low-temperature PECVD is effective for fabricating optimized VACNT arrays for thermal photodetectors.
• The developed EMT model accurately predicts the absorption characteristics of VACNTs, aiding in material design.
• These findings provide a foundation for integrating advanced CNT-based absorbers into infrared photodetector technologies.