Detection of mid-infrared by HgTe colloidal quantum dots at room temperature

Infrared sensing devices rely on narrow band gap semiconductors grown by expensive and complicated methods such as molecular beam epitaxy and chemical vapor deposition. Colloidal quantum dots (CQDs) offer a low-cost alternative to detect infrared light. In this study, we have successfully demonstrated synthesis of HgTe quantum dots, which can absorb midwave infrared (MWIR) at room temperature. The maximum absorption wavelength can be tuned by controlling the reaction time and reaction temperature of synthesis of the CQDs. Through simple drop-casting and cross-linking treatment, the HgTe CQDs MWIR detector can be fabricated, and we demonstrated detection of MWIR with a responsivity of 0.57 mA/W for infrared signal with wavelength of 3 μm at room temperature. The results pave the way for the development of low-cost midwave infrared detectors.