Midwave infrared detection has many uses, typically stemming from the sensing of vibrational structures, as in biological imaging or molecular spectroscopy, or the sensing of blackbody radiation, as in thermal imaging. Different infrared detector technologies each have their drawbacks. Bolometers are an inexpensive approach suffering from slow response speed and low frequency noise. InSb detectors generally require cryogenic cooling. Both InSb and HgCdTe detectors are prohibitively expensive for many applications.

Solution-processed materials are hoped to allow for vast improvements on the cost of infrared photon detectors with minimal losses to performance, expanding the range of feasible application. The most promising of these material approaches for use in the mid-infrared appears to be HgTe colloidal quantum dots. So far, the highest performing detectors of these are photovoltaics. This work focuses on the development of a circuit model for mid-infrared HgTe colloidal quantum dot photodiodes in order to investigate the limits of their performance in terms of measurable properties of the quantum dot material.

Specifically, this work presents significant improvements in detector external quantum efficiency through the incorporation of quantum dots with an improved synthesis and the management of leakage current with a guard ring. It presents a performant top-illuminated architecture and presents a detailed analysis of the temperature dependence of circuit model parameters, relating them to the dominant recombination mechanisms present in the dot material.