Near-omnidirectional InP nanowire-HBT photodetectors
A photodetector including a high electron mobility transistor (HEMT) device or an indium phosphide (InP)-based heterojunction bipolar transistor (HBT) device including a collector layer, a base layer formed on the collector layer and an emitter layer formed on the base layer. The photodetector also includes a nanowire array electrically coupled to the HEMT device or the base layer of the HBT device, and may include a first sub-array positioned on one side of the emitter layer and second sub-array positioned on an opposite side of the emitter layer. The nanowire array includes a plurality of spaced apart and conical-shaped InP nanowires encased in a transparent medium, and are operable to absorb light over a wavelength band of 400-925 nm and convert the light to an electrical signal that is received by the HEMT or HBT device.
1 . A detector comprising:
a semiconductor device; and
a nanowire array electrically coupled to the semiconductor device, said nanowire array including a plurality of spaced apart nanowires, said plurality of nanowires being operable to absorb radiation over a predetermined wavelength band and convert the radiation to an electrical signal that is received and amplified by the semiconductor device, wherein the semiconductor device is a heterojunction bipolar transistor (HBT) device including a collector layer, a base layer and an emitter layer, and wherein the nanowire array is separate from and formed directly on and in electrical contact with the base layer and laterally adjacent to the emitter layer.
2 . The detector according to claim 1 wherein the nanowire array includes a first nanowire sub-array position on one side of the emitter layer and a second nanowire sub-array positioned on an opposite side of the emitter layer.
3 . The detector according to claim 1 wherein the HBT device is an indium phosphide (InP) HBT device and the plurality of nanowires are InP nanowires.
4 . The detector according to claim 1 wherein the nanowire array covers an entire exposed portion of the base layer.
5 . The detector according to claim 1 wherein the detector is a photodetector and the nanowire array absorbs light.
6 . The detector according to claim 5 wherein the nanowire array absorbs light in 400-925 nm wavelength band.
7 . The detector according to claim 1 wherein each nanowire is conical-shaped.
8 . The detector according to claim 1 wherein the nanowire array includes a contact that is transparent to the radiation and in electrical contact with the plurality of nanowires.
9 . The detector according to claim 1 wherein a length and diameter of the plurality of nanowires is selected based on the wavelength band.
10 . The detector according to claim 1 wherein a length of the plurality of nanowires is in a range of 1-3 μm and a diameter of the nanowires is in a range of 50 nm to 200 nm.
11 . The detector according to claim 1 has a field-of-view of +/−60° with near unity absorption.
12 . A photodetector comprising:
an indium phosphide (InP)-based heterojunction bipolar transistor (HBT) device including a collector layer, a base layer formed on the collector layer and an emitter layer formed on the base layer; and
a nanowire array electrically coupled to the base layer, said nanowire array including a first sub-array positioned on one side of the emitter layer and second sub-array positioned on an opposite side of the emitter layer, each sub-array including a plurality of spaced apart and conical-shaped InP nanowires encased in a transparent medium, said plurality of nanowires being operable to absorb light over a wavelength band of 400-925 nm and convert the light to an electrical signal that is received by the base layer, wherein the nanowire array is separate from and formed directly on and in electrical contact with the base layer and laterally adjacent to the emitter layer.
13 . The photodetector according to claim 12 wherein the first and second sub-arrays each include a contact that is transparent to light opposite to the base layer and in electrical contact with the plurality of nanowires.
14 . The photodetector according to claim 12 wherein the nanowire array covers an entire exposed portion of the base layer.
15 . The photodetector according to claim 12 wherein a length of the plurality of nanowires is in a range of 1-3 μm and a diameter of the nanowires is in a range of 50 nm to 200 nm.
16 . The photodetector according to claim 12 has a field-of-view of +/−60° with near unity absorption.
17 . The photodetector according to claim 12 wherein the photodetector is part of a receiver for optical communications.
18 . The photodetector according to claim 12 wherein the photodetector is part of an imager.
19 . A detector comprising:
a semiconductor device; and
a nanowire array electrically coupled to the semiconductor device, said nanowire array including a plurality of spaced apart nanowires and an InP layer electrically coupled to the plurality of nanowires, said plurality of nanowires being operable to absorb radiation over a predetermined wavelength band and convert the radiation to an electrical signal that is received and amplified by the semiconductor device, wherein the semiconductor device is a high electron mobility transistor (HEMT) device including a channel layer, and wherein the nanowire array and the HEMT device are spaced apart on a common substrate and the InP layer is electrically coupled to the channel layer by a conductive bridge.
20 . The detector according to claim 19 wherein the substrate is an InP:Fe substrate and the channel layer is an InGaAs channel layer.