GaN photovoltaic leakage current and correlation to grain size
- 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, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 108; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CORRELATIONS
CRYSTAL GROWTH
CRYSTAL GROWTH METHODS
CURRENT DENSITY
CURRENTS
DIRECT ENERGY CONVERTERS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELEMENTS
EPITAXY
EQUIPMENT
FILMS
GALLIUM COMPOUNDS
GALLIUM NITRIDES
GOLD
GRAIN SIZE
INTERFACES
LAYERS
LEAKAGE CURRENT
MATERIALS
METALS
MICROSTRUCTURE
MOLECULAR BEAM EPITAXY
NITRIDES
NITROGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOELECTRIC EFFECT
PHOTOVOLTAIC CELLS
PHOTOVOLTAIC EFFECT
PHYSICAL PROPERTIES
PLASMA
PLATINUM
PLATINUM METALS
PNICTIDES
SEMICONDUCTOR MATERIALS
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SURFACES
THIN FILMS
TRANSITION ELEMENTS