QEBIC

2014 The Society for Information Display

HPY Publications , , ,

sid2“Cathodoluminescence quantum efficiency of quantum dot thin films”, H. P. Yoon, C. D. Bohn, Y. Lee, S. Ko, J. S. Steckel, S. Coe-Sullivan, N. B. Zhitenev, The Society for Information Display Technical Digests 45, 71–74, 2014.

1. Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
2. Maryland Nanocenter, University of Maryland, College Park, MD 20742, United States
3. QD Vision Inc., 29 Hartwell Ave., Lexington, MA 02421, United States

ABSTRACT. A thin film of quantum dots (QD) was used to visualize the local photo-response of polycrystalline CdTe solar cells by downconverting an electron beam of high energy to photons of visible light. The efficient photon generation in the QD film is compared to cathodoluminescence of the high-purity bulk semiconductors and phosphor.

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2013 AIP Advances

HPY Publications , , , ,

qebic“High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots”, H. P. Yoon, Y. Lee, C. D. Bohn, S. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, AIP Advances 3, 062112, 2013.

1. Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
2. Maryland Nanocenter, University of Maryland, College Park, MD 20742, USA
3. Department of physics, Worcester Polytechnic Institute, Worcester, MA 01602, USA
4. QD Vision Inc., 29 Hartwell Ave., Lexington, MA 02421, USA
5. Sandia National Laboratories, Livermore, CA 94550, USA

ABSTRACT. We report a fast, versatile photocurrent imaging technique to visualize the local photo response of solar energy devices and optoelectronics using near-field cathodoluminescence (CL) from a homogeneous quantum dot layer. This approach is quantitatively compared with direct measurements of high-resolution Electron Beam Induced Current (EBIC) using a thin film solar cell (n-CdS / p-CdTe). Qualitatively, the observed image contrast is similar, showing strong enhancement of the carrier collection efficiency at the p-n junction and near the grain boundaries. The spatial resolution of the new technique, termed Q-EBIC (EBIC using quantum dots), is determined by the absorption depth of photons. The results demonstrate a new method for highresolution, sub-wavelength photocurrent imaging measurement relevant for a wide range of applications.

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