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Solar blind photodetector based on epitaxial zinc doped Ga 2 O 3 thin film
Author(s) -
Alema Fikadu,
Hertog Brian,
Ledyaev Oleg,
Volovik Dmitry,
Thoma Grant,
Miller Ross,
Osinsky Andrei,
Mukhopadhyay Partha,
Bakhshi Sara,
Ali Haider,
Schoenfeld Winston V.
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600688
Subject(s) - responsivity , materials science , photodetector , epitaxy , optoelectronics , sapphire , dark current , thin film , doping , chemical vapor deposition , fabrication , annealing (glass) , detector , metalorganic vapour phase epitaxy , optics , nanotechnology , physics , laser , metallurgy , layer (electronics) , medicine , alternative medicine , pathology
We report on the fabrication and characterization of solar blind photodetectors (SBPs) based on undoped β‐Ga 2 O 3 and Zn doped (∼5 × 10 20 cm −3 ) β‐Ga 2 O 3 (ZnGaO) epitaxial films with cutoff wavelength of ∼260 nm. The epilayers were grown on c‐sapphire by the metal organic chemical vapor deposition technique and their structural, electrical and optical properties were characterized using various methods. As grown films have a large number of defects, resulting in detectors with enhanced internal gain, hence, high spectral responsivity >10 3 A/W. Post growth annealing in oxygen improved the quality of the epilayers, leading to detectors with reduced dark current (∼nA to ∼pA) and increased out of band rejection ratio. At 20 V bias, a ZnGaO detector showed a peak responsivity of 210 A/W (at 232 nm) and an out of band rejection ratio (i.e., R232 nm/R320 nm) of 5 × 10 4 . Alternatively, for a β‐Ga 2 O 3 detector these parameters were found to be five times and three times lower, respectively, suggesting that ZnGaO detectors have superior performance characteristics. These results provide a roadmap toward achieving high responsivity SBPs based on epitaxial ZnGaO films, laying a solid foundation for future applications.