The unipolar barrier is a new approach for control of dark currents in infrared photodetectors. First demonstrated in the nBn detector and then in the unipolar barrier photodiode, unipolar barriers have been shown to block surface leakage current. Unipolar barriers can also be implemented to filter out dark current components such as Shockley-Read-Hall current, direct band-to-band tunneling and trap-assisted tunneling, but are not useful for blocking diffusion currents. Current density-voltage characteristics of molecular-beam-epitaxy-grown InAs based unipolar barrier photodiodes are presented and analyzed, showing effective limiting of noise current mechanisms for different unipolar barrier photodiode architectures. R_oA data shows near Auger-limited device performance and R_oA values in excess of 1x10⁷ Ω-cm².

Date Published: 20 May 2011
PDF: 10 pages
Proc. SPIE 8012, Infrared Technology and Applications XXXVII, 80122T (20 May 2011); doi: 10.1117/12.884075

Published in SPIE Proceedings Vol. 8012:
Infrared Technology and Applications XXXVII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)