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Title: GaN photovoltaic leakage current and correlation to grain size

Abstract

GaN p-i-n solar PV structures grown by rf plasma assisted molecular beam epitaxy (MBE) produce high performance IV characteristics with a leakage current density of less than 1x10{sup -4} mA cm{sup -2} at 0.1 V forward bias and an on-resistance of 0.039 {Omega} cm{sup 2}. Leakage current measurements taken for different size diodes processed on the same sample containing the solar cells reveal that current density increases with diode area, indicating that leakage is not a large function of surface leakage along the mesa. Nonannealed Pt/Au Ohmic p-contacts produce a contact resistivity of 4.91x10{sup -4} {Omega} cm{sup -2} for thin Mg doped contact layers with sheet resistivity of 62196 {Omega}/{open_square}. Under concentrated sunlight the cells produce an open-circuit voltage of 2.5 V and short circuit currents as high as 30 mA cm{sup -2}. Multiple growths comprised the study and on each wafer the IV curves representing several diodes showed considerable variation in parasitic leakage current density at low voltages on some wafers and practically no variation on others. It appears that a smaller grain size within the GaN thin film accounts for higher levels of dark current.

Authors:
; ; ; ;  [1]
  1. Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)
Publication Date:
OSTI Identifier:
21476507
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 108; Journal Issue: 7; Other Information: DOI: 10.1063/1.3488886; (c) 2010 American Institute of Physics; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CORRELATIONS; CRYSTAL GROWTH; CURRENT DENSITY; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; GALLIUM NITRIDES; GOLD; GRAIN SIZE; INTERFACES; LAYERS; LEAKAGE CURRENT; MOLECULAR BEAM EPITAXY; PHOTOVOLTAIC EFFECT; PLASMA; PLATINUM; SEMICONDUCTOR MATERIALS; SOLAR CELLS; SURFACES; THIN FILMS; CRYSTAL GROWTH METHODS; CURRENTS; DIRECT ENERGY CONVERTERS; ELECTRIC CURRENTS; ELECTRICAL PROPERTIES; ELEMENTS; EPITAXY; EQUIPMENT; FILMS; GALLIUM COMPOUNDS; MATERIALS; METALS; MICROSTRUCTURE; NITRIDES; NITROGEN COMPOUNDS; PHOTOELECTRIC CELLS; PHOTOELECTRIC EFFECT; PHOTOVOLTAIC CELLS; PHYSICAL PROPERTIES; PLATINUM METALS; PNICTIDES; SIZE; SOLAR EQUIPMENT; TRANSITION ELEMENTS

Citation Formats

Matthews, K D, Chen, X, Hao, D, Schaff, W J, and Eastman, L F. GaN photovoltaic leakage current and correlation to grain size. United States: N. p., 2010. Web. doi:10.1063/1.3488886.
Matthews, K D, Chen, X, Hao, D, Schaff, W J, & Eastman, L F. GaN photovoltaic leakage current and correlation to grain size. United States. https://doi.org/10.1063/1.3488886
Matthews, K D, Chen, X, Hao, D, Schaff, W J, and Eastman, L F. 2010. "GaN photovoltaic leakage current and correlation to grain size". United States. https://doi.org/10.1063/1.3488886.
@article{osti_21476507,
title = {GaN photovoltaic leakage current and correlation to grain size},
author = {Matthews, K D and Chen, X and Hao, D and Schaff, W J and Eastman, L F},
abstractNote = {GaN p-i-n solar PV structures grown by rf plasma assisted molecular beam epitaxy (MBE) produce high performance IV characteristics with a leakage current density of less than 1x10{sup -4} mA cm{sup -2} at 0.1 V forward bias and an on-resistance of 0.039 {Omega} cm{sup 2}. Leakage current measurements taken for different size diodes processed on the same sample containing the solar cells reveal that current density increases with diode area, indicating that leakage is not a large function of surface leakage along the mesa. Nonannealed Pt/Au Ohmic p-contacts produce a contact resistivity of 4.91x10{sup -4} {Omega} cm{sup -2} for thin Mg doped contact layers with sheet resistivity of 62196 {Omega}/{open_square}. Under concentrated sunlight the cells produce an open-circuit voltage of 2.5 V and short circuit currents as high as 30 mA cm{sup -2}. Multiple growths comprised the study and on each wafer the IV curves representing several diodes showed considerable variation in parasitic leakage current density at low voltages on some wafers and practically no variation on others. It appears that a smaller grain size within the GaN thin film accounts for higher levels of dark current.},
doi = {10.1063/1.3488886},
url = {https://www.osti.gov/biblio/21476507}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 7,
volume = 108,
place = {United States},
year = {Fri Oct 15 00:00:00 EDT 2010},
month = {Fri Oct 15 00:00:00 EDT 2010}
}