AlGaN solar-blind Schottky photodiodes fabricated on 4H-SiC

Solar-blind AlGaN-based Schottky photodiodes grown on 4H-SiC substrate are reported. The fabricated devices demonstrate dark current density as low as 2.2times10
^-10
A/cm
²
at a reverse bias of 5 V. A zero-bias peak responsivity of 44 mA/W was achieved at 256 nm, corresponding to an external quantum efficiency of 21%. Under a low illumination power density of 10 nW/cm
²
, a rejection ratio of more than two orders of magnitude was observed in the wavelength range from 270 to 310 nm. A room-temperature solar-blind detectivity of 7.9times10
¹⁴
cmmiddotHz
^1/2
W
^-1
was estimated at 256 nm under zero bias