BERKELEY SENSOR & ACTUATOR CENTER
UC BERKELEY UC DAVIS
User: Guest |  Site Map |  My BSAC Profile
HOME  PROJECTS  THRUSTS  PUBLICATIONS  ABOUT BSAC  DIRECTORY  ALUMNI  FOR BSAC RESEARCHERS  EVENTS CALENDAR  SECURE LOGIN
Javey
     
 Lee
 Lin
 Wu
 

BPN667: Optical Absorption Study of 2-Dimensional III-Vs

Project ID BPN667
Website
Start Date Tue 2012-Jan-31 20:26:27
Last Updated Thu 2012-Feb-02 03:48:59
Abstract Recently, a new type of 2-D material, free standing InAs nanomembranes (thickness of 3 - 19 nm), as a representative of III-V semiconductors, was realized by layer transfer and this enables optical studies of 2-D InAs which were previously inaccessible, by decoupling those ultra-thin layers from original growth substrates to any optically transparent substrates. By using Fourier Transform Infrared (FTIR) spectroscopy, we directly observe the optical transitions from 2-D subbands, with energy spacing in line with the particle in the box model. Furthermore, it is found that the individual absorption steps from interband transitions plateau at ~1.6% for all samples, despite that the thickness is being changed by ~6x. The electron-photon interaction is also studied through Fermi’s Golden rule, we found that all the materials parameters such as carrier effective masses and bandgap cancel out, leading to a nearly material-independent absorptance of A_Q ≈ 8πα/(3nr) for each optical transition step, where nr is between 3 and 4 for most semiconductors in the wavelength range of interest. The work here presents a universal law of absorption for 2-D semiconductors. Besides its significance in the basic understanding of electron-photon interactions in quantum confined semiconductors, this result provides a new insight toward the use of 2-D semiconductors for novel photonic and optoelectronic devices.
Status New
Funding Source Federal
IAB Research Area NanoPlasmonics, Microphotonics & Imaging
Researcher(s) Hui Fang, Kuniharu Takei
Advisor(s) Ali Javey
Detailed Information
Secure Access

Private Abstract
Research Report
Poster
Summary Slide
Can’t view video click here
Active Feedback (or Request for Response)

 

  • Copyright Notification: All papers downloaded from this site are © University of California or the publisher, all rights reserved. Contact the BSAC Webmaster for permission related to copyrighted materials.
  • Links on these pages to commercial sites do not represent endorsements by UC or its affiliates.
  • Privacy Policy
  • Contact Us

   webmaster@bsac.eecs.berkeley.edu
  User logged in as: Guest
  User Idle since: August 22, 2014, 12:41 pm