Synthesis of High-Density Vertical Carbon Nanotube Arrays for Infrared Scene Conversion Films

Carbon nanotubes are ideal infrared-absorbing materials that can be applied in array-scale infrared image generation technology under low-temperature conditions. Vertical carbon nanotube arrays are grown by PECVD method and the effects of various growth parameters on morphological characteristics and crystallization quality are investigated. The height and density of vertical carbon nanotube arrays increase linearly with the growth temperature, time, and hydrogen flow rate. Under optimized growth conditions, vertical carbon nanotube arrays approximately with a height of 10 µm and a density of 170 nanotubes per square micron are successfully synthesized. Additionally, a silicon substrate-carbon nanotube array composite microstructure is designed and fabricated by MEMS technology. The low thermal conductivity of the silicon oxide layer and the physical isolation from micropillars effectively minimize heat conduction between adjacent regions, reducing thermal crosstalk. Optimizing the pixel structure of the light absorption layer enhances the light absorption rate, enabling the detection of finer temperature variations and producing clearer thermal images. The apparent temperature of composite chip under infrared radiation is ≈445 K, and the photothermal conversion efficiency reaches 51.07%, laying the foundation for improving the sensitivity of conversion chips.