Infrared absorbance of vertically-aligned multi-walled CNT forest as a function of synthesis temperature and time
Journal article, 2020

In this paper, the growth of optimized vertically aligned multi-walled carbon nanotube (VA-MWCNT) forests by LPCVD method for use in a large-area absorber in infrared detectors is presented. The effect of synthesis temperature (500−700 °C) and time (1−10 min) on the optical absorption coefficient in the infrared (2−20 μm) is investigated by FT-IR measurement at various incident angles (15-80°). The structural properties of VA-MWCNT are characterized by SEM, TEM and Raman spectroscopy. Spectral measurements show an increasing absorption with the height of the forest that results at increased synthesis time and temperature. However, the absorption coefficient decreases with increasing synthesize time and temperature, while it is also affected by other properties, such as diameter, density, alignment, and uniformity. Moreover, the reduction in absorption at oblique incident angles demonstrates the relevance of surface properties. Finally, a circular graphite waveguide system is used to model the absorption characteristics of an MWCNT forest.


Growth temperature


Growth time



Amir Mirza Gheitaghy

Delft University of Technology

Mohammadamir Ghaderi

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Sten Vollebregt

Delft University of Technology

Majid Ahmadi

Delft University of Technology

Reinoud F. Wolffenbuttel

Delft University of Technology

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Guo Qi Zhang

Delft University of Technology

Materials Research Bulletin

0025-5408 (ISSN)

Vol. 126 110821

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics



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