skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current

Abstract

We report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface and in the GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. The comprehensive understanding presented in this work suggests that performance benefits of dilute nitride microwire solar cells can be achieved by further tuning of the epitaxial quality of the underlying materials.

Authors:
 [1]; ;  [2];  [3];  [4]; ;  [1];  [5]
  1. Graduate Program of Materials Science and Engineering, University of California, San Diego, La Jolla, California 92037 (United States)
  2. Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92037 (United States)
  3. Department of Nanoengineering, University of California, San Diego, La Jolla, California 92037 (United States)
  4. Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
  5. (United States)
Publication Date:
OSTI Identifier:
22597743
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPARATIVE EVALUATIONS; ELECTRIC POTENTIAL; ELECTRICAL FAULTS; ELECTRONS; ETCHING; GALLIUM PHOSPHIDES; IONS; MOLECULAR BEAM EPITAXY; MOLECULAR BEAMS; MORPHOLOGY; PERFORMANCE; P-N JUNCTIONS; QUANTUM EFFICIENCY; SHELLS; SOLAR CELLS; SURFACES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Sukrittanon, Supanee, Liu, Ren, Pan, Janet L., Breeden, Michael C., Jungjohann, K. L., Tu, Charles W., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, Dayeh, Shadi A., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, and Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92037. Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current. United States: N. p., 2016. Web. doi:10.1063/1.4959821.
Sukrittanon, Supanee, Liu, Ren, Pan, Janet L., Breeden, Michael C., Jungjohann, K. L., Tu, Charles W., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, Dayeh, Shadi A., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, & Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92037. Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current. United States. doi:10.1063/1.4959821.
Sukrittanon, Supanee, Liu, Ren, Pan, Janet L., Breeden, Michael C., Jungjohann, K. L., Tu, Charles W., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, Dayeh, Shadi A., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu, and Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92037. Sun . "Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current". United States. doi:10.1063/1.4959821.
@article{osti_22597743,
title = {Radial direct bandgap p-i-n GaNP microwire solar cells with enhanced short circuit current},
author = {Sukrittanon, Supanee and Liu, Ren and Pan, Janet L. and Breeden, Michael C. and Jungjohann, K. L. and Tu, Charles W., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu and Dayeh, Shadi A., E-mail: ctu@ece.ucsd.edu, E-mail: sdayeh@ece.ucsd.edu and Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92037},
abstractNote = {We report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface and in the GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. The comprehensive understanding presented in this work suggests that performance benefits of dilute nitride microwire solar cells can be achieved by further tuning of the epitaxial quality of the underlying materials.},
doi = {10.1063/1.4959821},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = {Sun Aug 07 00:00:00 EDT 2016},
month = {Sun Aug 07 00:00:00 EDT 2016}
}
  • Here, we report the demonstration of dilute nitride heterostructure core/shell microwire solar cells utilizing the combination of top-down reactive-ion etching to create the cores (GaP) and molecular beam epitaxy to create the shells (GaNP). Systematic studies of cell performance over a series of microwire lengths, array periods, and microwire sidewall morphologies examined by transmission electron microscopy were conducted to shed light on performance-limiting factors and to optimize the cell efficiency. We also show by microscopy and correlated external quantum efficiency characterization that the open circuit voltage is degraded primarily due to the presence of defects at the GaP/GaNP interface andmore » in the GaNP shells, and is not limited by surface recombination. Compared to thin film solar cells in the same growth run, the microwire solar cells exhibit greater short circuit current but poorer open circuit voltage due to greater light absorption and number of defects in the microwire structure, respectively. Finally, we present performance benefits of dilute nitride microwire solar cells and show that it can be achieved by further tuning of the epitaxial quality of the underlying materials.« less
  • This patent describes a photovoltaic cell. It comprises: a transparent substrate; a transparent front conductive layer formed on the substrate; a p-type layer formed on the front conductive layer; an i-layer of amorphous silicon formed on the p-layer; an n-type sandwich structure of amorphous silicon formed on the i-layer, the n-type sandwich structure including firs, second, and third n-layers successively formed on one another, the first n-layer being formed on the i-layer to form a rectifying junction therewith, the second n-layer being formed on the second n-layer, and the third n-layer being formed on the second n-layer, and the secondmore » n-layer having an optical bandgap wider than respective optical bandgaps of the first and third n-type layers and the i-layer; the second n-layer having a thickness at least two times the thickness of each of the first the third n-layers; and a back contact layer of conductive material formed on the third n-layer to form an ohmic contact therewith.« less
  • In this study, we demonstrate –2.05 eV dilute nitride GaNP solar cells on GaP substrates for potential use as the top junction in dual-junction integrated cells on Si. By adding a small amount of N into indirect-bandgap GaP, GaNP has several extremely important attributes: a direct-bandgap that is also tunable, and easily attained lattice-match with Si. Our best GaNP solar cell ([N] –1.8%, E g –2.05 eV) achieves an efficiency of 7.9%, even in the absence of a window layer. This GaNP solar cell's efficiency is 3× higher than the most efficient GaP solar cell to date and higher thanmore » other solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance are demonstrated.« less