Recent News

  • September 2020: Debarghya wins an AVS Graduate Research Award!

  • September 2020: Jun’s Paper “High mobility large area single crystal III–V thin film templates directly grown on amorphous SiO2 on silicon” has been written up in SemiconductorToday!

  • April 2020: Debarghya Sarkar wins the USC Viterbi Ballhaus Dissertation Award.

  • April 2020: Prof. Kapadia wins the 2020 AVS Peter Mark Memorial Award.

  • April 2020: Debarghya Sarkar wins the USC ECE Best Dissertation Award.

  • April 2020: Nick Mehlman wins the Philip Beigler Memorial Award.

  • February 2020: Debarghya successfully defended his Ph.D Thesis, “Building Blocks for 3D Integrated Circuits: Single Crystal Compound Semiconductor Growth and Device Fabrication on Amorphous Substrates.”

  • February 2020: Ragib’s paper “Performance Limits of Graphene Hot Electron Emission Photoemitters” is published in Physical Review Applied.

  • June 2019: Debarghya’s paper “Direct Growth of Crystalline III-Vs on Amorphous Dielectrics Using a Combination of Epitaxial and Non-Epitaxial Methods” wins Best Student Paper at the 2019 Electronic Materials Conference!

  • December 2018: Debarghya is a 2018-2019 Ming Hsieh Institute Ph.D. Scholar!

  • May 2018: Fatemeh successfully defended her Ph.D Thesis, “Integrated Photonics Assisted Electron Emission Devices.”

  • April 2018: Debarghya wins the Honorable mention for the USC EE Graduate Teaching Award!

Recent Papers

Performance Limits of Graphene Hot Electron Emission Photoemitters

Ragib Ahsan, Mashnoon Alam Sakib, Hyun Uk Chae, and Rehan Kapadia
Phys. Rev. Applied 13, 024060 – Published 24 February 2020
It is shown that, through appropriate selection of photon energy, optical power density, and applied electric field, hot electron emission can be used to create ultrahigh current electron emitters with ultrafast temporal responses in both the single particle and ensemble heating regimes.

Tunable Onset of Hydrogen Evolution in Graphene with Hot Electrons

Hyun Uk Chae, Ragib Ahsan,  Jun Tao, Stephen B. Cronin, Rehan Kapadia
Nano Letters
By rigorously considering the key scattering mechanisms, we show that the injected hot electrons can significantly increase the available electron flux at high energies. These results show that semiconductor–insulator–graphene devices are a platform which can tune the electrochemical reaction rate via multiple mechanisms.

Our Research Areas

Semiconductors on Anything

We develop novel growth techniques for single crystalline semiconductors on technologically relevant, non-epitaxial substrates. Using these techniques, we then fabricate electronic and photonic devices for next generation architectures and systems.

Recent Papers

  1. Sarkar, et al. “Confined Liquid Phase Growth of Crystalline Compound Semiconductors on Any Substrate“, ACS Nano, DOI: 10.1021/acsnano.8b01819.
  2. Sarkar, et al. “Buffer insensitive optoelectronic quality of InP-on-Si with templated liquid phase growth“, JVST B, 36 (3), 031204 (2018).  
  3. Sarkar, et al. “Mimicking Biological Synaptic Functionality with an Indium Phosphide Synaptic Device on Silicon for Scalable Neuromorphic Computing”, ACS Nano, DOI:10.1021/acsnano.7b08272, 2018.
  4. Lin, et al. A Scalable Indium Phosphide Thin-Film Nanophotonics Platform for Photovoltaic and Photoelectrochemical Devices”, ACS Nano, 11 (5), 2017.

Current Funding

Heterogeneous III-V CMOS on Si via Direct Growth”, Principal Investigator, NSF, 8/1/16-7/31/19

Crystalline Electronic and Photonic Materials without an Epitaxial Template”, Principal Investigator, Semiconductor Research Corporation, 1/1/18 – 12/31/20

Past Funding

III-V Active Pixel, Ultrahigh Performance Sensors for Shortwave Infrared Focal Plane Arrays at Very Low Cost”, Principal Investigator, NASA JPL,5/1/2017 – 9/1/2017

Integrated Photonics for Electron Emitters

We have shown that integrated photonic circuits hold significant promise for ultra-fast and efficient modulation of electron emitters.

Recent Papers

  1. Rezaeifar, et al. “Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters”, Journal of Vacuum Science and Technology B, 35 (6), 062202.
  2. Rezaeifar, et al. “Efficient and Ultrafast Optical Modulation of On-Chip Thermionic Emission Using Resonant Cavity Coupled Electron Emitters”, Journal of Vacuum Science & Technology B, 34 (4), 041228, 2016.

Current Funding

Optical Cavity Enhanced Electron Emitters”, Principal Investigator, AFOSR Young Investigator Program, 7/15/16-7/14/19.

Carbon Nano-tube (CNT) cathodes for Normal Conducting RF Guns”, Principal Investigator; DOE SBIR Phase II Subcontract, Radiabeam, LLC. 6/1/17-1/9/19.

Broadband Ultrafast Photon Source”, Principal Investigator, AFOSR DURIP, 7/1/18 – 6/31/19.

Hot Electron Electrochemistry

To study hot electrons and their use in electrochemistry, we explore both electrical and optical means of non-equilibrium electron generation and study how that modifies electrochemical transfer rates.

Recent Papers

  1. B. Hou, L. Shen, H. Shi, R. Kapadia, S.B. Cronin, “Hot Electron-Driven Photocatalytic Water Splitting”, Physical Chemistry Chemical Physics, 19, 2877-2881, 2017.
  2. Hou, F. Rezaeifar, J. Qiu, G. Zeng, R. Kapadia, S.B. Cronin. “Prevention of surface recombination by electrochemical tuning of TiO2-passivated photocatalysts”, Applied Physics Letters, 111 (14), 141603, 2017.

Current Funding

A Novel Platform for Studying Hot Electron Spectroscopy of Electrochemical and Photoelectrochemical Reactions”, Co-Principal Investigator (PI: Steve Cronin), ACS Petroleum Research Fund, 9/1/15-8/31/18.