Self quenched quantum dot avalanche photodetector for mid-infrared single photon detection

• A single photon detector (SPD) for mid IR wavelength is proposed and its performance is studied.
• The structure is designed for self-quenching operation.
• Dark count rate and detection efficiency of the proposed SPD is calculated at different temperatures.
• Dynamic operation of detector is studied by calculation of self-quenching and self-recovering times.

In this paper a single photon detector with operating wavelength of 6 μm is proposed and its performance characteristics are studied. Intersubband absorption of single photons in quantum dot layers leads to creation of photoelectrons which are injected to multiplication region and under above breakdown condition a large output pulse is generated. The detector is designed for self quenching operation in which an additional layer called transient carrier buffer (TCB) is used for trapping of backward avalanche generated holes at the interface of TCB and charge layer. The accumulated holes impose an additional charge in such a way that the voltage across the multiplication region drops and the output is quenched. A model is developed to analyze the performance of detector and results of simulation predict detection efficiency about 12% at T = 150 K. Also the quenching and recovering performance of detector is studied and results show that both higher temperatures and higher bias improve dynamics of detector. However higher temperatures result in higher dark count rate.