Photonics Society at UCSB
  • Home
  • Members
    • Alumni
  • Calendar
  • Events
    • Lectures >
      • Industry Perspective Lectures
      • IPS Lectures
      • Student Lectures
      • Alumni Lectures
      • OSA Lectures
    • Outreach Events
    • Women in Photonics Week >
      • WIPW 2019
      • WiPW 2018
      • WiPW 2017
      • WiPW 2016
    • Light Science Workshop >
      • Light Science 2018
      • Light Science 2017
    • Day of Light >
      • Day of Light 2019
      • 2015 Symposium
    • Banquet >
      • Banquet 2022
      • Banquet 2019
      • Banquet 2016
      • Banquet 2014
    • QIS >
      • QIS2022
      • QIS2021
    • Social Events
    • Sign-up for Student Talks
  • Education
    • Education Home
    • After-School Science >
      • Light-Pipes: Controlling Light
      • DIY Holograms
      • Color Mixing
      • LaserComm
      • Fluorescence
    • Classes
    • Outreach Events
    • Outreach Kits 2020
  • Home
  • Members
    • Alumni
  • Calendar
  • Events
    • Lectures >
      • Industry Perspective Lectures
      • IPS Lectures
      • Student Lectures
      • Alumni Lectures
      • OSA Lectures
    • Outreach Events
    • Women in Photonics Week >
      • WIPW 2019
      • WiPW 2018
      • WiPW 2017
      • WiPW 2016
    • Light Science Workshop >
      • Light Science 2018
      • Light Science 2017
    • Day of Light >
      • Day of Light 2019
      • 2015 Symposium
    • Banquet >
      • Banquet 2022
      • Banquet 2019
      • Banquet 2016
      • Banquet 2014
    • QIS >
      • QIS2022
      • QIS2021
    • Social Events
    • Sign-up for Student Talks
  • Education
    • Education Home
    • After-School Science >
      • Light-Pipes: Controlling Light
      • DIY Holograms
      • Color Mixing
      • LaserComm
      • Fluorescence
    • Classes
    • Outreach Events
    • Outreach Kits 2020
Picture
Picture
Picture
Picture

New possibilities in nitride photonics exploiting porosity

2/21/2022

 
Picture

Picture

​​Dr. Rachel A. Oliver
Director of the Cambridge Centre for GaN
University of Cambridge
Picture

Friday March 4th at 1:00pm PST in Henley Hall 1010 and via Zoom
Pizza Provided in-person!
Porous semiconducting nitrides are effectively a new class of semiconducting material, with properties distinct from the monolithic nitride layers from which devices from light emitting diodes (LEDs) to high electron mobility transistors are increasingly made. The introduction of porosity provides new opportunities to engineer a range of properties including refractive index, thermal and electrical conductivity, stiffness and piezoelectricity. Quantum structures may be created within porous architectures and novel composites may be created via the infiltration of other materials into porous nitride frameworks.    A key example of the application of porous nitrides in photonics is the fabrication of high reflectivity distributed Bragg reflectors (DBRs) from alternating layers of porous and non-porous GaN.  These reflectors are fabricated from epitaxial structures consisting of alternating doped and undoped layers, in which only the conductive, doped layers are electrochemically etched. Conventionally, trenches are formed using a dry-etching process, penetrating through the multilayer, and the electrochemical etch then proceeds laterally from the trench sidewalls.  The need for these trenches then limits the device designs and manufacturing processes within which the resulting reflectors can be used. We have developed a novel alternative etching process, which removes the requirement for the dry-etched trenches, with etching proceeding vertically from the top surface through channels formed at naturally-occurring defects in the crystal structure of GaN. This etch process leaves an undoped top surface layer almost unaltered and suitable for further epitaxy. This new defect-based etching process provides great flexibility for the creation of a variety of sub-surface porous architectures on top of which a range of devices may be grown.  Whilst DBR structures enable improved light extraction from LEDs and the formation of resonant cavities for lasers and single photon sources, recent development also suggest that thick, subs-surface porous layers may enable strain relaxation to help improve the efficiency of red microLEDs for augmented reality displays.  Meanwhile, the option of filling pores in nitride layers with other materials provides new opportunities for the integration of nitrides with emerging photonic materials, such as the hybrid-perovskite semiconductors, with perovskites encapsulated in porous nitride layers demonstrating greatly improved robustness against environmental degradation.
Picture
Images from https://www.nature.com/articles/srep45344
Picture

    Mailing List

    Supported By

    Picture
    Thorlabs designs and produces a variety of optomechanical and optoelectronic components in 15 facilities around the globe. Thorlabs seeks to listen and serve its customers with over 20,000 products available. ​
    Picture
    Founded in 2018, Nexus Photonics has developed integrated photonics ready to scale. Smaller, lighter and faster, their platform outperforms industry benchmarks, and operates in an ultra-broadband wavelength range from ultraviolet to infrared to support a wide breadth of practical applications.

    Picture

    Archives

    March 2023
    February 2023
    January 2023
    October 2022
    September 2022
    July 2022
    June 2022
    May 2022
    April 2022
    March 2022
    February 2022
    November 2021
    October 2021
    September 2021
    July 2021
    May 2021
    April 2021
    March 2021
    January 2021
    December 2020
    October 2020
    August 2020
    May 2020
    April 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    July 2019
    June 2019
    May 2019
    April 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    June 2018
    February 2018
    January 2018
    October 2017
    July 2017
    June 2017
    March 2017
    February 2017
    October 2016
    September 2016
    July 2016
    April 2016
    February 2016
    January 2016
    October 2015
    September 2015
    August 2015
    July 2015
    May 2015
    January 2015
    October 2014
    September 2014
    July 2014
    May 2014
    April 2014
    March 2014
    September 2013
    July 2013
    March 2013
    February 2013
    October 2012

    Categories

    All
    Alumni Lectures
    Industry Perspective Lectures
    IPS Distinguished Lectures
    Lectures
    OSA Lectures
    Outreach Events
    Past Events
    Social Events
    Student Lecture Series

Powered by Create your own unique website with customizable templates.