GaN photovoltaic leakage current and correlation to grain size

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3488886· OSTI ID:21476507

Matthews, K D; Chen, X; Hao, D; Schaff, W J; Eastman, L F ^[1]

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1. Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)

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.

• OSTI ID: 21476507
• Journal Information: Journal of Applied Physics, Vol. 108, Issue 7; Other Information: DOI: 10.1063/1.3488886; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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