量子科学论坛

（第七十期）

日期和时间Date & Time：1-July-2022 2:00PM

线上会议Zoom Meeting： ID：662 921 9901   Passcode: 763638

报告人Speaker ：Dr. Santanu Manna, Postdoctoral Fellow， Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria

主持人Host ：Quanyong Lu  Researcher, BAQIS

题目Title：GaAs quantum dots grown by droplet etching epitaxy as quantum light sources

摘要Abstract 

World is now heavily dependent on semiconductor devices; Si is leading the microelectronics industry and III-V compound semiconductors for light sources. Because of the indirect bandgap, Si can’t compete with direct bandgap III-V semiconductors regarding light emission, whether its classical or quantum. GaAs and InP are mostly studied III-V platforms for the same. In my talk, I will concentrate on GaAs quantum dots regarding its applications for single/entangled quantum emitters (~780 nm), which is a very hot topic now. Since this is a lattice matched case, typical Stranski-Krastanov growth method is unnecessary here and droplet method appears into the picture. Using droplet etching of nanoholes followed by GaAs filling, strain-free as well as highly symmetric dots could be produced and this system can generate single photon as well as entangled photons. Next, I will show that the p-i-n diode structure containing GaAs QD can overcome blinking issue, and that could be useful for achieving high visibility of two-photon interference from two different remote dots to establish quantum network and computing schemes and also enhancing the key rates in quantum key distribution. Lastly, I would describe the present research trend in the community which concerns moving from ~780 or ~900 nm to telecom C-band entangled photon emitters. 

报告人简介About the speaker

Santanu Manna received both Masters and PhD Degree in Physics from Indian Institute of Technology Kharagpur, India in 2008 and 2014, respectively. As a visiting postdoc fellow, he joined the NanoLab in the Department of Physics, University of Trento, Italy to work with Prof. Lorenzo Pavesi on silicon photonics during 2014-2015. Later on, he joined the Center for Quantum Devices, ECE Department, McCormick School of Engineering in Northwestern University, United States as a postdoctoral fellow to work on InP based quantum cascade lasers with Prof. Manijeh Razeghi during 2016-2018. Later on, he joined the Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria as a postdoctoral researcher in 2018 to work with Prof. Armando Rastelli on III-V quantum dot based single/entangled photon emitters and he is now a university assistant in the same place. In a nutshell, his research interest lies in the epitaxial growth by molecular beam epitaxy, processing and measurements on III-V semiconductor (GaAs, InP) based quantum devices like single/entangled photon emitters for quantum communication, quantum cascade laser based frequency comb and THz emitter for recognizing different molecular fingerprints. Presently he is working on blinking-free quantum dot as entangled photon source for quantum key distribution. Till now he has published more than 40 international journal articles; he is the recipient of the prestigious ‘University Assistant’ position in the JKU Linz; he has been recently offered an ‘Assistant Professor’ position in the prestigious IIT Delhi, India and also awarded ‘Young faculty incentive fellowship’.