Low-noise back-illuminated AlxGa1-xN-basedp-i-n solar-blind ultraviolet photodetectors |
| |
Authors: | Ting Li Lambert DJH Wong MM Collins CJ Yang B Beck AL Chowdhury U Durpuis RD Campbell JC |
| |
Affiliation: | Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX; |
| |
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: | |
|
|