Semiconducting nanowire fluid sensor

Abstract

Nanowire fluid sensors are provided. The fluid sensors comprise a first electrode, a second electrode, and at least one nanowire between the first electrode and the second electrode. Each nanowire is connected at a first end to the first electrode and at a second end to the second electrode. Methods of fabricating and operating the fluid sensor are also provided.

1 . A fluid sensor comprising:
 a first electrode;   a second electrode; and   at least one nanowire between said first electrode and said second electrode, with said at least one nanowire connected at a first end to said first electrode and at a second end to said second electrode.   
     
     
         2 . The fluid sensor of  claim 1  wherein said first electrode comprises an electrically conductive material. 
     
     
         3 . The fluid sensor of  claim 2  wherein said first electrode is selected from the group consisting of silicon, tungsten, and gold. 
     
     
         4 . The fluid sensor of  claim 1  wherein said second electrode comprises at least one metal selected from the group consisting of gold, tungsten, titanium, platinum, aluminum, and copper. 
     
     
         5 . The fluid sensor of  claim 1  wherein said at least one nanowire comprises a material selected from the group consisting of silicon, germanium, Si 1-x Ge x , GaAs, and InP. 
     
     
         6 . The fluid sensor of  claim 1  wherein said at least one nanowire has a length within a range of 0.5 to 20 μm. 
     
     
         7 . The fluid sensor of  claim 1  wherein said at least one nanowire has a diameter within a range of 5 to 300 nm. 
     
     
         8 . The fluid sensor of  claim 1  wherein said at least one nanowire is provided with a functional coating specific for detecting a specific species in a fluid. 
     
     
         9 . The fluid sensor of  claim 8  wherein said functional coating and said specific species in the fluid are selected from the group consisting of DNA or PNA and complementary DNA. 
     
     
         10 - 25 . (canceled) 
     
     
         26 . A method of operating a fluid sensor, said method comprising:
 providing a fluid sensor comprising
 a first electrode, 
 a second electrode, and 
   at least one nanowires between said first electrode and said second electrode, with said at least one nanowire connected at a first end to said first electrode and at a second end to said second electrode;   introducing at least one fluid to said fluid sensor; and   determining an aspect of said at least one fluid.   
     
     
         27 . The method of  claim 26  wherein said first electrode comprises an electrically conducting material. 
     
     
         28 . The method of  claim 27  wherein said electrically conducting material is selected from the group consisting of silicon, tungsten, and gold. 
     
     
         29 . The method of  claim 26  wherein said second electrode comprises at least one metal selected from the group consisting of gold, tungsten, titanium, platinum, aluminum, and copper. 
     
     
         30 . The method of  claim 26  wherein said at least one nanowire comprises a material selected from the group consisting of silicon, germanium, Si 1-x Ge x , GaAs, and InP. 
     
     
         31 . The method of  claim 26  wherein said at least one nanowire has a length within a range of 0.5 to 20 μm. 
     
     
         32 . The method of  claim 26  wherein said at least one nanowire has a diameter within a range of 5 to 300 nm. 
     
     
         33 . The method of  claim 26  wherein said at least one nanowire is provided with a functional coating specific for detecting a specific species in a fluid. 
     
     
         34 . The method of  claim 33  wherein said functional coating and said specific species in said fluid are selected from the group consisting of DNA or PNA and complementary DNA. 
     
     
         35 . The method of  claim 26  wherein an aspect of said at least one fluid comprises at least one of: (1) determining if a species is present in said fluid, (2) determining the quantity of the species in said fluid, and (3) determining the identity of said species. 
     
     
         36 . The method of  claim 35  wherein said at least one species in the fluid modulates conductivity of said at least one nanowire. 
     
     
         37 . The method of  claim 36  wherein said modulation occurs by changing the physical size of the conducting region in depletion mode operation. 
     
     
         38 . The method of  claim 36  wherein said modulation occurs by inducing mobile carriers near external surfaces of said at least one nanowire in accumulation or inversion mode operation. 
     
     
         39 . A method of operating an array of fluid sensors, said method comprising:
 providing an array of fluid sensors, each fluid sensor comprising
 a first electrode, 
 a second electrode, and 
   at least one nanowire between said first electrode and said second electrode, with said at least one nanowire connected at a first end to said first electrode and at a second end to said second electrode;   introducing at least one fluid to said fluid sensor; and   determining an aspect of said at least one fluid.   
     
     
         40 . The method of  claim 39  wherein said determining step includes determining the amount of each species present from the response of one fluid sensor in said array. 
     
     
         41 . The method of  claim 39 , wherein each fluid sensor is provided with a functional coating having a different response to different species and wherein said determining step includes:
 determining a signal from each fluid sensor in said array upon exposure to said fluid to form a set of signals; and   processing said set of signals to determine a quantity of each species in said fluid being analyzed.