Broader impact - Single photon detectors are the enabling devices for several important conventional and quantum technology applications, such as quantum key distribution, quantum imaging and single molecule spectroscopy. In spite of the growing importance of these applications, there has been little progress towards the development of compact solid-state detectors and arrays specifically designed for single photon counting. Single photon p-n junction detectors do not provide the necessary performance and their operation has never been optimized for this application. The PI intends to address this problem by presenting a novel class of single photon detectors based on semiconductor nano-structures and by developing a new numerical simulation approach for their design and optimization. The theory and simulation techniques developed will also be useful in the study of a broad range of carrier transport and light detection phenomena in nano-structured materials and devices.
The educational plan includes developments in undergraduate and graduate programs, support for high school teachers, and an educational program for developing countries. A key feature is the use of simulation tools to improve the teaching of semiconductor physics and technologies at all educational levels.
Intellectual Merit - The PI proposes the use of two novel detector concepts that work on different physical principles by taking advantage of nano-structure devices. The proposed device structures are intended to overcome some of the disadvantages (dark and afterpulse counts, lack of tunability and necessity of cooling) of the current single photon detector designs and provide additional functionalities, e.g. tunability. The first device is based on intersubband optical absorption in a multi-quantum-well or quantum dot layers, followed by a multiplication region. The second device uses a layer of quantum dots embedded in a high electron mobility transistor structure. In the proposed work, a new numerical simulation technique that the PI is developing will be used to design and optimize a new class of single photon detectors. The new numerical simulation approach is based on a microscopic model that describes the details of the detection, multiplication and carrier transport processes and their time evolution. This technique does not have the drawbacks of the macroscopic models, provides a better description of the physics and operation of single photon detectors, and is complementary to analytical methods being developed by other groups. The simulation technique will also be used to show how the performance of the current generation of APDs can be improved.
