Infrared Absorbance of Distributed-Size HgTe Quantum Dots Under Diffuse Reflectance

Colloidal quantum dots (CQDs) have various uses in photodetectors, solar cell devices and spectroscopic signal enhancement. In this paper, we synthesize mercury telluride (HgTe) CQDs and study the effect of the QDs size distribution on their infrared absorbance spectrum. The resulting dots are characterized using x-ray diffraction analysis and the size was found to be about 8.6 nm with a standard deviation of about 2 nm using high-resolution transmission electron microscope. The produced CQDs are optically characterized using Fourier transform infrared spectrometer in diffuse reflectance mode in the wavelength range from 3 to 11 μm. The absorption shows a wide absorption edge rather than a sharp feature. The measured data are fitted with a sum of a polynomial and five gaussian functions to extract the absorption lines of the QDs.