Recent Activities

Title of the talk: Temperature-dependent analysis of Ge1-xSnx-based single-photon avalanche diodes for cryogenic applications. 

Authors: Harshvardhan Kumar and Jyoti Tater

In this work, we present the first proof of the temperature-dependent analysis of Ge0.93Sn0.07-based single-photon avalanche diodes (SPADs) designed for cryogenic applications. The performance of the proposed SPAD is outstanding across cryogenic, room, and elevated temperatures. Moreover, the comparison with previously reported SPADs suggests that the proposed GeSn SPAD design could be a viable candidate for future developments in quantum computing and communication technologies. 

Title of the talk: Impacts of Temperature on the Performance of Ge_(1-x) Sn_x-based Mid-infrared Light-Emitting Diodes on Si Substrate. 

Authors: Harshvardhan, Yash Bijawat, and P. Susthitha Menon

In this work, we present silicon (Si)-based double-heterojunction light-emitting diodes (DHLEDs) that incorporate the GeSn alloy into the active layer. This study examines the effects of temperature (T) and Sn concentration on performance metrics, including terminal currents, emitted power, and emission spectrum. The benchmark demonstrates that the proposed GeSn LEDs could be a potential light source in the SWIR band for both cryogenic and room-temperature applications. 

We were honored to extend an invitation to Prof. Meyya Meyyappan, Honorary Professor, IIT Guwahati (Ex-Chief Scientist for Exploration Technology and Director of the Center for Nanotechnology, NASA Ames Research Center in Silicon Valley, USA), for an invited talk at LNMIIT, Jaipur. He delivered the invited talk on "Printed and Flexible Electronics and Devices: A Tutorial."

The key points and outcome of the talk include:

• The rapid emergence of the Internet of Things era that has led to increased research activities in the area of printed and flexible electronics. The activities range from ink development and characterization and printing tool and process development to obtain desirable characteristics of printed conductors, semiconductors, dielectrics, and others, and demonstration of various printed devices on a wide variety of flexible substrates, including paper, plastics, and textiles.

• An overview of the above topics and applications, including printed antennas, EMI shields, gas sensors, supercapacitors, photodetectors, and others.

• Advances in printer development, such as plasma jet printing, as an alternative to inkjet and aerosol jet printing. 

We were honored to extend an invitation to Prof. Prasanta Kumar Datta, Professor (HAG) in the Department of Physics at the IIT KGP, for an invited talk at LNMIIT, Jaipur. He delivered the invited talk on "Experimental Methods of Ultrafast Science." Additionally, Prof. Datta engaged with the students of LNMIIT and the SiPhRG, discussing the current research facilities available at his lab, future career opportunities, internships, and the various admission processes for higher studies, including M.Tech/M.S. and Ph.D. programs at IIT Kharagpur. 

Title of the talk: Ge/GeSn p-n-i-p  Heterojunction Phototransistors for Short-wave Infrared Applications: Experimental Demonstrations. 

In this talk, Dr. Kumar discussed the problems associated with existing materials and photonic devices, and how we can mitigate these issues with novel group-IV alloys—such as SiGeSn—and devices, including heterojunction phototransistors grown on Si. Moreover, I discussed the design and fabrication of GeSn-based p-n-i-p heterojunction phototransistors for SWIR applications, as well as the effects of Sn concentration and varying optical power on electro-optical characterization. 

Attending SEMICON 2025 as a visitor was a tremendous privilege. Our group members participated in numerous discussions and engaged with various semiconductor and VLSI companies, including LAM Research, Applied Materials, Tata Electronics, ASML, Capgemini, and many many more. We gained insights into their ongoing projects, university programs, collaborations, and career opportunities within the semiconductor and VLSI sectors. 

We were excited to host Dr. Balaji Gururajan for his talk and MoU at the LNM Institute of Information Technology, Jaipur. Dr. Balaji delivered the talk on 'design and fabrication of semi-transparent solar cell'. Dr. Balaji Gururajan, who is currently an Assistant Professor in the College of Electrical and Communication Engineering at Yuan Ze University, Taiwan, where he also serves as the Chief of International Affairs. We sincerely appreciate Dr. Balaji Gururajan for graciously accepting our invitation to deliver such an insightful talk.

We sincerely appreciate both the online and offline audience for joining the talk..!! 

We were excited to host Dr. Michael Oehme for the invited talk in the Department of ECE at The LNM Institute of Information Technology, Jaipur. Dr. Michael Oehme delivered the talk on 'SiGeSn alloys for Silicon photonics, with an emphasis on photonic integrated chips, including detectors and light emitters for communication and lidar applications.' Additionally, Dr. Michael Oehme discussed the motivation, current challenges, and potential solutions regarding group-IV alloys. We gathered several ideas from his talk. Dr. Michael Oehme stands out as a pioneer in the field of silicon photonics. Dr. Michael Oehme has published more than 250 papers in SCI-refereed journals and conferences, with over 6000 citations. We sincerely appreciate Dr. Michael Oehme for graciously accepting our invitation to deliver such an insightful talk.

We sincerely appreciate both the online and offline audience for joining the talk..!! 

Recently, we had a group introduction and discussion with Prof. Prasanta K. Basu (Retired Professor, IRPE, University of Calcutta). The interaction was excellent and extremely significant. We discussed the group's current and future works and challenges associated with silicon photonics and potential solutions. 

Group Introduction and Discussion: Bhavika Agarwal; Neha Soni; Trishad Bisawa; Jyoti Tater; Yash Bijawat; Arindam Chaudhary; Som Mudgil; Shubh Jaiswal 

Title: Break the Fundamental Limit of Group-IV Photonics: Room-temperature Photodetectors, Sensors, and Light Emitters

In this talk, I discussed the current challenges of group IV alloys, our approaches, and their impact. Take away of this talk are (i) the present and future of silicon photonics, (ii) group-IV alloy-based detectors: advanced detectors such as HPTs and WG-integrated detectors, etc., (iii) electrically-injected and optically-pumped all-group-IV light emitters: recent progress, and (iii) mid-infrared sensors using all-group-IV alloys for trace gases sensing.