Physics 838 Graduate Student Seminar

In 1990, a seminar was initiated for QMC (formerly CNAM/CSR) graduate students in order to present their research to the other students, postdocs, and faculty in the Center. In addition to fostering a rich, collaborative environment in which students learn about the breadth and scope of research being done in QMC, the idea of this series is to teach several crucial skills to our students:

1) How to present their research in a clear and time-efficient way to an audience that was not expert in their area of research;

2) How to best answer questions during their presentations;

3) How to ask good questions when in an audience (or interview), in particular about research beyond their own narrow PhD topic.

In this seminar, students submit formalized feedback to each weekly presenter, providing informative information about presentation style, research content and tips for improvement.

Best Speaker Awards

At the end of each term, a cash prize award is given for the best student and postdoc presentations based on class feedback scores. Previous winners are listed here:

2025 (fall) Jared Dans (student)

2025 (spring)  Jarryd Horn (student)

2024 (fall) Jared Erb (student)

2023 (fall) Jared Erb (student), Peter Czajka (postdoc)

2022 (fall) Sungha Baek (student), Keenan Avers (postdoc)

2020 (fall) Shukai Ma 

2019 (spring) Rui Zhang (student), Tarapada Sarkar (postdoc)

2018 (fall) Chris Eckberg (student), Jen-Hao Yeh (postdoc)

2015 Paul Syers, Jasper Drisko

2014 Sean Fackler, Paul Syers,

2013 Kevin Kirshenbaum, Kirsten Burson

2012 Baladitya Suri, Kristen Burson

2011 (fall) Sergii Pershoguba, Ted Thorbeck

2011 (spring) Anirban Gangopadhyay, Baladitya Suri

2010 (fall) Christian J. Long, Tomasz M. Kott

2010 (spring) Tomasz M. Kott, Kevin Kirshenbaum

2009 (fall) Arun Luykx, Jen-Hao Yeh

PHYS838C Seminar: Ashish Alexander

Calendar
Physics 838 Seminar
Date
03.23.2026 4:00 pm - 5:00 pm
Location
John S. Toll Room 1201

Description

Impact of substrate and resonator surface treatments on microwave loss of high-Q titanium nitride superconducting resonators

 

This work explores the influence of surface treatments on the resonator performance of single-crystal titanium nitride (TiN) films grown on sapphire substrates using plasma-assisted molecular beam epitaxy. Various surface treatments are performed on the substrate prior to growth, and on the complete resonator devices prior to wire bonding in order to reduce two level system loss.

 The impact of sapphire surface cleaning prior to thin film growth is investigated through six wafers. The set of wafers are cleaned using an ex-situ cleaning of either organic solvents or a Piranha etch and an in-situ treatment consisting of a thermal anneal under either UHV, atomic-nitrogen, or atomic-oxygen conditions. The finished resonators are treated with either a hydrofluoric or piranha etch.

 The effect of various cleaning treatments on the sapphire wafers and the TiN thin film are characterized using AFM, SEM and HRXRD. XPS analysis of the acid-cleaned resonator surfaces indicate that both acid etches reduces the O-1s peak intensity. Acid-cleaning the resonators consistently doubles the internal quality factor, with a mean quality factor close to 1 million, compared to control samples that are cleaned with organic solvents.





Host: Chris Richardson