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Title: Overcoming diffusion-related limitations in semiconductor defect imaging with phonon-plasmon-coupled mode Raman scattering

Carrier diffusion is of paramount importance in many semiconductor devices, such as solar cells, photodetectors, and power electronics. Structural defects prevent such devices from reaching their full performance potential. Although a large carrier diffusion length indicates high material quality, it also implies increased carrier depletion by an individual extended defect (for instance, a dislocation) and obscures the spatial resolution of neighboring defects using optical techniques. For commonly utilized photoluminescence (PL) imaging, the spatial resolution is dictated by the diffusion length rather than by the laser spot size, no matter the spot is at or below the diffraction limit. We show how Raman imaging of the LO phonon-plasmon-coupled mode can be used to recover the intrinsic spatial resolution of the optical system, and we demonstrate the effectiveness of the technique by imaging defects in GaAs with diffraction-limited optics, achieving a 10-fold improvement in resolution. Furthermore, by combining Raman and PL imaging, we can independently and simultaneously determine the spatial dependence of the electron density, hole density, radiative recombination rate, and non-radiative recombination rate near a dislocation-like defect, which has not been possible using other techniques.
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ; ORCiD logo [2]
  1. Univ. of North Carolina, Charlotte, NC (United States); Wuhan Univ. of Technology (China)
  2. Univ. of North Carolina, Charlotte, NC (United States)
  3. Davidson College, Davidson, NC (United States)
  4. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2047-7538
Grant/Contract Number:
AC36-08GO28308; W911NF-10-1-0524; W911NF-16-1-0263; 51702245
Accepted Manuscript
Journal Name:
Light, Science & Applications
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2047-7538
Nature Publishing Group
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); US Army Research Office (ARO); National Natural Science Foundation of China (NNSFC); China Scholarship Council (CSC)
Country of Publication:
United States
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; diffraction; diffusion; gallium arsenide; III-V semiconductors; image resolution; optical systems; phonons; plasmons; semiconductor devices
OSTI Identifier: