Array of nanowires in a single cavity with anti-reflective coating on substrate

Abstract

An embodiment relates to image sensor comprising one or more nanowires on a substrate of a cavity, the nanowire being configured to transmit a first portion of an electromagnetic radiation beam incident on the sensor, and the substrate that absorbs a second portion of the electromagnetic radiation beam incident on the sensor, wherein the first portion is substantially different from the second portion. The substrate could have a anti-reflective material. The ratio of a diameter of the cavity to a diameter of the nanowire could be at less than about 10.

What is claimed: 
     
         1 . An image sensor comprising one or more upstanding nanowires on a substrate,
 wherein the nanowires are configured to transmit a first portion of an electromagnetic radiation incident on the sensor but not to transmit a second portion of the electromagnetic radiation incident on the sensor;   wherein the substrate is configured to absorb the second portion of the electromagnetic radiation beam incident on the sensor,   wherein the first portion has frequencies higher than a cutoff frequency and the second portion has frequencies lower than the cutoff frequency.   
     
     
         2 . The sensor of  claim 1 , wherein the second portion comprises at least a portion of electromagnetic radiation that comes out from the nanowire. 
     
     
         3 . The sensor of  claim 1 , wherein the substrate comprises an anti-reflective material on a front side of the substrate that is exposed to the electromagnetic radiation beam incident on the sensor. 
     
     
         4 . The sensor of  claim 1 , wherein at least one of the one or more upstanding nanowires has a diameter above 100 nm. 
     
     
         5 . The sensor of  claim 1 , wherein the nanowire is configured to separate wavelengths of the electromagnetic radiation beam incident on the nanowire at a selective wavelength. 
     
     
         6 . The sensor of  claim 1 , wherein at least one of the one or more upstanding nanowires comprises GaAs. 
     
     
         7 . The sensor of  claim 1 , wherein the substrate comprises GaAs. 
     
     
         8 . The sensor of  claim 1 , wherein the sensor comprises a plurality of nanowires and is configured to have a substantially minor change in an optical response of the nanowire with a 10° change in a direction of the electromagnetic radiation beam incident on the sensor. 
     
     
         9 . The sensor of  claim 1 , wherein each of the nanowires is configured to separate wavelengths of the electromagnetic radiation beam incident on the nanowire through at a selective wavelength, the sensor further comprising a pair of photosensitive elements comprising a central photosensitive element and a peripheral photosensitive element, wherein the central photosensitive element is operably coupled to the nanowire and the peripheral photosensitive element is operably coupled to the substrate around the nanowire. 
     
     
         10 . The sensor of  claim 1 , wherein the nanowires are active elements configured to detect wavelengths of electromagnetic radiation transmitted through the nanowires. 
     
     
         11 . The sensor of  claim 10 , wherein the active element is a photodiode. 
     
     
         12 . A device comprising the sensor of  claim 1 , wherein the device is an image sensor. 
     
     
         13 . The device of  claim 1 , wherein the nanowires comprise a waveguide. 
     
     
         14 . The device of  claim 13 , further comprising a passivation layer around the waveguide. 
     
     
         15 . The device of  claim 13 , further comprising a metal layer around the waveguide. 
     
     
         16 . The device of  claim 12 , wherein the device comprises a filter that cuts off visible light and passes IR light. 
     
     
         17 . The device of  claim 12 , further comprising a cladding surrounding the nanowires, wherein the nanowires have a nanowire index of refraction (n 1 ), and the cladding has a cladding index of refraction (n 2 ), wherein n 1 >n 2 , or n 1 =n 2 . 
     
     
         18 . The device of  claim 13 , wherein the selective wavelength is a function of the diameter of the waveguide. 
     
     
         19 . The device of  claim 13 , further comprising at least a pair of metal contacts with at least one of the metal contacts being contacted to the waveguide. 
     
     
         20 . The sensor of  claim 1 , wherein the nanowires absorb the first portion. 
     
     
         21 . The sensor of  claim 1 , wherein the nanowires are configured to store charge carriers generated by the first portion of the electromagnetic radiation beam in the nanowires. 
     
     
         22 . The device of  claim 13 , wherein the nanowires are configured to store charge carriers generated by the first portion of the electromagnetic radiation beam in the nanowires.