SOLAR BLIND ULTRA VIOLET (UV) DETECTOR AND FABRICATION METHODS OF THE SAME

1 . A device comprising:

a substrate;

a plurality of pixels;

a plurality of nanowires in each of the plurality of pixel;

wherein the plurality of nanowires are configured to detect a UV emitting source without interference from solar radiation.

2 . The device of claim 1 , wherein the plurality of nanowires have an absorptance above 25% for UV light with a wavelength from 0.12 to 0.34 micron.

3 . The device of claim 1 , wherein each of the plurality of nanowires comprises a core and a cladding surrounding the core, wherein the core has a higher refractive index than the cladding.

4 . The device of claim 1 , wherein each of the plurality of the nanowires comprises a coupler disposed on an end of each of the nanowire away from the substrate, the coupler being functional to guide radiation into the nanowires.

5 . The device of claim 1 , wherein the nanowires have a height from about 0.1 μm to about 5 μm; the cladding has a thickness of about 10 nm to about 200 nm.

6 . The device of claim 1 , wherein the nanowires have a pitch from about 0.2 μm to about 2 μm.

7 . The device of claim 1 , wherein the nanowires detect UV radiation in a solar-blind UV region by converting UV radiation in the solar-blind UV region to an electrical signal.

8 . The device of claim 7 , wherein the device further comprises electrical components configured to detect the electrical signal.

9 . The device of claim 7 , wherein the device is functional to detect the electrical signal from the nanowires in different pixels separately.

10 . The device of claim 1 , wherein each of the nanowires comprises a photodiode or forms a photodiode with the substrate, wherein the photodiode is functional to convert at least a portion of UV radiation in a solar-blind UV region impinged on the nanowires.

11 . The device of claim 10 , wherein each of the nanowires comprises

a first heavily doped semiconductor layer,

a lightly doped semiconductor layer or an intrinsic semiconductor layer,

a second heavily doped semiconductor layer, and

a metal silicide layer;

wherein the first heavily doped semiconductor layer is disposed on the lightly doped semiconductor layer or the intrinsic semiconductor layer;

the lightly doped semiconductor layer or the intrinsic semiconductor layer is disposed on the second heavily doped semiconductor layer;

the second heavily doped semiconductor layer is disposed on the metal silicide layer;

the metal silicide layer is disposed on the substrate;

the first heavily doped semiconductor layer is of an opposite type from the second heavily doped semiconductor layer; and

wherein the first heavily doped semiconductor layer, the lightly doped semiconductor layer or the intrinsic semiconductor layer, and the second heavily doped semiconductor layer form the photodiode.

12 . The device of claim 11 , wherein the device further comprises a common electrode disposed on and electrically connected to ends of all the nanowires, wherein the common electrode is substantially transparent to UV radiation in a solar-blind UV region.

13 . The device of claim 12 , wherein the common electrode is made of graphene.

14 . The device of claim 12 , further comprising a metal grid on the common electrode, the metal grid configured to provide mechanical support for the common electrode.

15 . The device of claim 10 , wherein each of the nanowires comprises

a core of lightly doped semiconductor,

an intermediate shell of intrinsic semiconductor and

an outer shell of doped semiconductor;

wherein the intermediate shell is conformally disposed over the core;

the outer shell is conformally disposed over the intermediate shell;

the outer shell is of an opposite type from the core; and

the outer shell, the intermediate shell and the core form the photodiode.

16 . The device of claim 15 , wherein each nanowire further comprises

a heavily doped semiconductor layer of the same type as the core, and a metal silicide layer;

wherein the heavily doped semiconductor layer and a metal silicide layer are sandwiched between the core and the substrate;

the intermediate shell and the outer shell do not contact the heavily doped semiconductor layer and the metal silicide layer; and

the metal silicide layer is in contact with the substrate and forms electrical contact to the substrate.

17 . The device of claim 10 , wherein the photodiode is an avalanche photodiode.

18 . The device of claim 1 , wherein space between the nanowires is filled with an oxide layer.

19 . A solar-blind image sensor, comprising the device of claim 1 and electronic circuitry functional to detect electrical signals generated by the nanowires of the device.

20 . The solar-blind image sensor of claim 19 , wherein the electronic circuitry comprises a high voltage supply.