Title :
Low-noise back-illuminated AlxGa1-xN-based p-i-n solar-blind ultraviolet photodetectors
Author :
Li, Ting ; Lambert, D.J.H. ; Wong, M.M. ; Collins, C.J. ; Yang, B. ; Beck, A.L. ; Chowdhury, U. ; Durpuis, R.D. ; Campbell, J.C.
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA
fDate :
4/1/2001 12:00:00 AM
Abstract :
We report the growth, fabrication and characterization of Al0.4Ga0.6N-Al0.6Ga0.4N back-illuminated, solar-blind p-i-n photodiodes. The peak responsivity of the photodiodes is 27 and 79 mA/W at λ≈280 nm for bias voltages of 0 V and -60 V, respectively, with a UV-to-visible rejection ratio of more than three decades (at 400 nm). These devices exhibit very low dark current densities (~5 nA/cm2 at -10 V). At low frequencies, the noise exhibits a 1/f-type behavior. The noise power density is S0≈5×10-25 A2/Hz at -12.7 V and the detectivity (D*) at 0 V is estimated to be in the range of 4×1011-5×1013 cm·Hz1/2 /W. Time-domain pulse response measurements in a front-illumination configuration indicate that the devices are RC-time limited and show a strong spatial dependence with respect to the position of the incident excitation, which is mainly due to the high resistivity of the p-type Al0.4Ga0.6 N layer
Keywords :
III-V semiconductors; MOCVD; aluminium compounds; current density; electrical resistivity; gallium compounds; p-i-n photodiodes; photodetectors; semiconductor device noise; semiconductor growth; ultraviolet detectors; -10 V; -12.7 V; -60 V; 0 V; 1/f-type behavior; 280 nm; 400 nm; Al0.4Ga0.6N-Al0.6Ga0.4 N; RC-time limited; UV-to-visible rejection ratio; bias voltages; characterization; detectivity; fabrication; front-illumination configuration; growth; high resistivity; incident excitation; low frequencies; low-noise back-illuminated AlxGa1-xN-based p-i-n solar-blind ultraviolet photodetectors; noise power density; p-type Al0.4Ga0.6 N layer; peak responsivity; strong spatial dependence; time-domain pulse response measurements; very low dark current densities; Dark current; Density measurement; Fabrication; Frequency; Low-frequency noise; PIN photodiodes; Power measurement; Pulse measurements; Time domain analysis; Voltage;
Journal_Title :
Quantum Electronics, IEEE Journal of
