The Group

Current Group Members

 

Postdoctoral Researchers

 

 

Fang's photo

Dr. Fang Liu

Ph.D. from University of Pennsylvania

I am using femtosecond two-photon photoemission spectroscopy with extreme-UV lasers to explore electronic structure and dynamics of self-assembled semiconductors. In my spare time, I enjoy baking and feeding the other people you see on this webpage.

Email: fl2454@columbia.edu

 

 

 


Maehrlein_Portrait

Dr. Sebastian F. Maehrlein

Ph.D. from Free University of Berlin

My central research interest evolves around lattice-driven phenomena in solids to control material properties on ultrafast time scales. In my Ph.D. thesis at the Fritz-Haber-Institute of the Max Planck Society, I studied phonon driven spin dynamics and demonstrated a novel nonlinear light-matter coupling scheme by making use of intense THz-electric fields. Now, I investigate how specific lattice properties may lead to charge carrier protection and defect tolerance in emerging semiconductors. In my free time, I study spin properties of plastic discs or explore NY’s art scene.

 

 

 


Feifan-photo

Dr. Feifan Wang

Ph.D. from Peking University

I try to complete the solar-chemical energy conversion puzzle from the aspects of photophysics and surface/interface chemistry. During my PhD program, I studied the solid-state semiconductor nanomaterials for photocatalysis and photoelectrochemical cells, with focusing on material synthesis and performance characterization, more about the chemistry and molecular engineering. Here, I am establishing some fundamental understanding of photophysics in the novel optoelectronic materials through synthesizing andprobing the carrier screening in these model systems. After work, I like to jog, read, and learn cooking food.

 

 


Yusong Bai

Dr. Yusong Bai

Ph.D. from Duke University

During my Ph.D., my research emphasis was on interrogating and managing photo-induced electronically excited-state dynamics of various supermolecular to nanoscale structures, including ethyne-bridged highly-conjugated (porphinato)metal(II) architectures, semiconducting single-walled carbon nanotubes, etc. Currently, I investigate charge transfer dynamics at donor/acceptor interfaces.

 

 

 

 


xyz_bio_pic

Dr. Mark Ziffer

Ph.D. from University of Washington

My research focuses on using EUV time resolved two photon photoemission spectroscopy to study electronic structure and charge carrier dynamics in 2D semiconductor monolayers and heterostructures based on superatomic solids and transition metal dichalcogenides. I received my PhD from the University of Washington working with David Ginger, where I used electric field modulation spectroscopy and luminescence spectroscopy techniques to study exciton electronic structure and charge recombination in hybrid organic-inorganic perovskite and organic semiconductors. In my spare time I like exploring new places and trying new foods, which luckily NYC has no shortage of.

 

 


dav

Dr. Lin Zhou – Research Scientist

Ph.D. from Nanjing University

I am currently an Adjunct Research Scientist in the Department of Chemistry at Columbia University. Before joining the XYZ Group, I became an Associate Professor of Quantum Electronics and Optics Engineering in the College of Engineering and Applied Sciences, Nanjing University. I received my PhD from Nanjing University in 2012. My research interests are broadly in nanophotonics and plasmonics for advanced energy materials and devices. I am now focusing on manipulation of interactions between light and two dimensional materials with rationale designed nanophotonic structures.

 

 


doyk

Dr. Doyk Hwang

Ph.D. from Seoul National University

In the XYZ Group, I am working on understanding the fundamentals of light-matter interactions, specifically exciton-polaritons in microcavities, with various spectroscopic techniques. During my Ph.D. with Prof. Seong Keun Kim, I was interested in photoexcited processes in organic molecules and photovoltaics which I investigated through the lens of femtosecond spectroscopic techniques including second-order nonlinear spectroscopy. In my free time I enjoy searching for good music, reading great literature, going to contemporary art museums, or just wandering through the beautiful parks of NYC.

 


Yanan

Dr. Yanan Dai

Ph.D. from University of Pittsburgh

My PhD research was focused on imaging of femtosecond dynamics of space-time structured surface evanescent waves using interferometric time-resolved coherent multi-photon photoemission microscopy, and studying their physical properties such as spin angular momentum, field chirality and topological spin textures. Now I am trying to explore the rich electronic and excitonic properties of bilayer heterostructures composed of transition metal dichalcogenides, using time-resolved and angle-resolved photoemission spectroscopy with a femtosecond laser-based excitation source.

 

 


Qiuyang

Dr. Qiuyang Li

Ph.D. from Emory University

received my Ph.D. in Physical Chemistry focusing on the charge separation/recombination and exciton transport/dissociation in semiconductor nanocrystals for solar-to-hydrogen conversion and lasing applications. In the XYZ group, my research is mainly on ultrafast laser spectroscopic studies on exciton, electron, and phonon dynamics in new and emerging semiconductors. In my spare time, I enjoy movies, foods, badminton, and swimming.

 

 


CRubioVerdu

Dr. Carmen Rubio Verdú

I am a joint postdoc with the Pasupathy Group in the Department of Physics. I use Low-temperature Scanning Tunneling Microscopy/Spectroscopy and am studying stronglycorrelated phenomena in bilayer 2D materials.

 

 

 

 

 

 



Graduate Students

 

 

IMG_8749

Xinjue Zhong

B.S. in Chemistry from University of Science and Technology of China

I am working on Scanning Tunneling Microscopy/Spectroscopy to study the electronic properties of novel super-atom solids.

 

Email: xz2374@columbia.edu

 

 


Jue (1)

Jue Wang

B.S. in Chemistry from Peking University

I use time-resolved optical spectroscopy and microscopy to study interlayer excitons in two-dimensional van der Waals heterostructures. Before this dimension reduction, I worked on hot carriers and polaron physics in lead halide perovskites. When getting my B.S. at Peking University, I researched single-molecule biophysics of DNA repair and met Rachael with whom I spend my spare time and travel around the world.

Email: jw3227@columbia.edu

 

 

 


Prakriti

Prakriti Joshi

B.S. in Chemistry from the University of Chicago

I am interested in phonon dynamics in hybrid semiconductors. I apply a range of spectroscopic techniques including time-resolved optical Kerr effect and transient absorption.

Email: ppj2102@columbia.edu

 

 

 

 


Kihong

Kihong Lee

B.S. in Chemistry from University of California, Berkeley

I was born and raised in South Korea. At U.C. Berkeley, I researched heterogeneous catalysis of metal nanoparticles under the guidance on Prof. Gabor Somorjai. For my graduate studies, I am studying superatom solids and their optical properties as a joint student between Prof. Xiaoyang Zhu and Prof. Xavier Roy.

Email: kl2797@columbia.edu

 

 


IMG_1031

Drew Schlaus

B.S. in Chemistry from University of Redlands

I investigate the fundamental light matter interactions in polariton condensates using kerr gated ultrafast time-resolved photo-luminescence microscopy. It was my initial love of photography which years ago sparked my interest in spectroscopy. I am still an avid photographer but you will frequently find me screeching karaoke, enjoying the baked deserts from fellow group members, exploring the New York city skyline, and adventuring through the frontiers of scientific research.

Email: as4942@columbia.edu

 

 


Michael

Michael Scott Spencer

B.S. in Chemistry & Physics from West Virginia University

I work on polariton lasing and the application of novel spectroscopic techniques. In my free time, I enjoy the outdoors, especially hiking.

Email: mss2257@columbia.edu

 

 

 

 


Felisa

Felisa Conrad-Burton

B.S. in Chemistry from George Mason University

I use time-resolved optical techniques to explore and understand the fundamental processes of new singlet fission materials. I also enjoy taking full advantage of the variety of food and Broadway shows available in NYC, as well as fattening up my fellow group members with copious amounts of homemade pie.

Email: fsc2118@columbia.edu

 

 

 


yfliu_group website

Yufeng Liu

B.S. in Chemistry from Fudan University

I worked on infrared photodissociation spectroscopy of cluster ions during my undergraduate. Here, bidding farewell to the gas phase and entering the regime of solid state, I resume my connection with optical experiments and clusters by exploring the electron-phonon coupling in superatomic materials. You can constantly find my practicing the piano in the lounge after work

Email: yl3983@columbia.edu

 

 


image_123986672

Wenjing Wu

B.S. in Materials Science Engineering from East China University of Science and Technology

I am currently a Master’s student in the Materials Science and Engineering Department. During my undergrad at ECUST my study was mainly focused on inorganic materials. Here, I am working on two dimensional materials with rationale designed nanophotonic structures with Dr. Lin Zhou. Rock music and chocolate light up my life.

 

 



Undergraduate Students

 

C43D7EBA-1322-4B85-A0A2-98A79F3E9588

Angela Ye

Pursuing B.S. in Chemical Engineering at Columbia University

In general, I am interested in research on two-dimensional van der Waals heterostructures as well as new materials for energy storage and conversion. Previously, I worked on projects studying metal and metal oxide nanoparticles as catalysts for use in energy technology. When not in the lab or class, I can be found eating through Chinatown, playing the cowbell in the marching band, or watching The Good Place.

 

 

 


IMG_20190527_140850

Nicholas Olsen

Pursuing B.S. in Physical Chemistry at University of Utah

I am a summer researcher with the MRSEC REU program. I work with Dr. Mark Ziffer studying electron phonon coupling in ferroelectric semiconductors. The opportunity to learn from the rest of the group excited me greatly. After completing this summer research experience I will return to Salt Lake City to complete my undergraduate  degree studying Physical Chemistry at the University of Utah. When I get a spare moment, I enjoy getting lost in the mountains, desert, and now the city.

 

 



 

Past Group Members

 

Graduate Students

Tyler Evans (Ph.D., 2018) – Postdoc, UC Berkeley (Leone Group)

Timothy Atallah (Ph.D., 2017) – Postdoc, UCLA (Caram Group)

Kristopher Williams (Ph.D., 2017) – Postdoc, MIT (Tisdale Group)

Nicholas Monahan (Ph.D., 2015) – Rutherford Research Fellow, Victoria University of Wellington

Cory Nelson (Ph.D., 2015) – Intel Corporation

Xiaoxi Wu (Ph.D., 2015) – Postdoc, Stanford University (Lindenberg Group)

Kin-Wai Wesker Lei (Ph.D., 2014) – Novati Technologies Inc.

Adam Garland (Ph.D., 2014) – Water Lens, LLC

Joshua Morris (Ph.D., 2013) – Assistant Professor, Georgia Gwinnett College

John Tritsch (Ph.D., 2013) – Intel Corporation

Kenrick Williams (Ph.D., 2012) – Lecturer, Green River College

Williams Tisdale (Ph.D., 2010) – Associate Professor, MIT

Travis Mills (Ph.D., 2009) – Associate Professor, St. Paul’s College

Loren Kaake (Ph.D. 2009) – Assistant Professor, Simon Frasier University

Matthew Goertz (Ph.D., 2009) – Donaldson Company

Yang Deng (Ph.D., 2008) – L’Oreal

Chad Lindstrom (Ph.D., 2006) – Air Force Research Lab

Gregory Dutton (Ph.D., 2006) – National Institute of Justice (DOJ)

Taewoon Cha (Ph.D., 2005) – Apple, Inc.

Joo H. Kang (Ph.D., 2005) – Dow Chemical Company

Yong Seok Jun (Ph.D., 2004) – Associate Professor, Konkuk University, Korea

Ryan C. Major (Ph.D., 2003) – Hysitron, Inc.

Hanfu Wang (Ph.D., 2001) – Associate Professor, National Center for Nanoscience and Technology of China


Postdocs

Florian Geyer (2017-2018) – BASF

Kiyoshi Miyata (2015-2018) – Assistant Professor, Kyushu University (Onda Group)

Daniel Niesner (2014-2017) – Postdoc, University of Erlangen-Nuremberg (Fauster Group)

M. Tuan Trinh (2013-2016) – Adjunct Associate Research Scientist, University of Michigan (Rand Group)

Haiming Zhu (2014-2016) – Professor, Zhejiang University

Manuel Marks (2013-2015) – Bausch (Germany)

Heungman Park (2011-2013) – Assistant Professor, Texas A&M University-Commerce

Lei Shen (2009-2013) – Professor, Wuhan University of Technology

Wai-lun Chan (2009-2012) – Assistant Professor, University of Kansas

A. Jailaubekov (2009-2012) – Staff Scientist, Cymer Corporation

Manuel Ligges (2010-2011) – Univ. Essen, Germany

Luis Miaja-Avila (2010-2012) – NIST, Colorado

Abe Wolcott (2010-2012) – Assistant Professor, San Jose State University

Matthias Muntwiler (2005-2009) – Group Leader, Paul Scherer Institute, Switzerland

Qinxing Yang (2007-2009) – Associate Professor, Harbin Institute of Technology, China

Vassil Boiadjiev (2000-2002) – Lecturer, Temple University