CAREER: Theoretical Investigation of Single Photon Detectors for Quantum Technology: A Nano-structure Devices Approach

更广泛的影响-单光子探测器是几个重要的传统和量子技术应用的使能设备，如量子密钥分发，量子成像和单分子光谱。尽管这些应用越来越重要，但专门为单光子计数设计的紧凑型固态探测器和阵列的发展进展甚微。单光子p-n结探测器不能提供必要的性能，并且它们的操作从未针对这种应用进行过优化。PI打算通过提出一类基于半导体纳米结构的新型单光子探测器，并通过开发一种新的设计和优化数值模拟方法来解决这个问题。所开发的理论和模拟技术也将有助于研究纳米结构材料和器件中的载流子输运和光探测现象。该教育计划包括本科和研究生课程的发展，对高中教师的支持，以及发展中国家的教育计划。一个关键的特点是使用模拟工具，以提高半导体物理和技术的教学在所有教育水平。智力优势——PI提出使用两种新的探测器概念，它们利用纳米结构器件在不同的物理原理下工作。提出的器件结构旨在克服当前单光子探测器设计的一些缺点（暗脉冲和后脉冲计数，缺乏可调性和冷却的必要性），并提供额外的功能，例如可调性。第一种装置是基于多量子阱或量子点层中的子带间光吸收，然后是倍增区。第二种装置使用嵌入在高电子迁移率晶体管结构中的量子点层。在提出的工作中，PI正在开发的一种新的数值模拟技术将用于设计和优化一类新的单光子探测器。新的数值模拟方法基于微观模型，该模型描述了探测、倍增和载流子输运过程及其时间演化的细节。这种技术没有宏观模型的缺点，提供了对单光子探测器的物理和操作的更好的描述，并且是其他小组正在开发的分析方法的补充。仿真技术还将用于展示如何改进当前一代apd的性能。

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.