Cantilevered probes having piezoelectric layer, treated section, and resistive heater, and method of use for chemical detection

• US 8,136,385 B2
• Filed: 08/27/2007
• Issued: 03/20/2012
• Est. Priority Date: 03/11/2003
• Status: Active Grant

• Current Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Original Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Inventors: Adams, Jesse D., Rogers, Benjamin S., Sulchek, Todd A.
• Primary Examiner(s): Raevis, Robert R
• Application Number:
  US11/845,661
• Publication Number:
  US 20100267164A1
• Time in Patent Office: 1,667 Days
• Field of Search: None
• US Class Current: 73/31.05
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 30/14 Liquid environment
• CPC Class Codes: G01Q 60/42 Functionalisation

Abstract

The invention provides a liquid cell for an atomic force microscope. The liquid cell includes a liquid cell housing with an internal cavity to contain a fluid, a plurality of conductive feedthroughs traversing the liquid cell housing between the internal cavity and a dry side of the liquid cell, a cantilevered probe coupled to the liquid cell housing, and a piezoelectric drive element disposed on the cantilevered probe. The cantilevered probe is actuated when a drive voltage is applied to the piezoelectric drive element through at least one of the conductive feedthroughs. A method of imaging an object in a liquid medium and a method of sensing a target species with the liquid cell are also disclosed.

Claims

1. A chemical sensor system comprising:

a first cantilevered probe comprising;

a piezoelectric layer;

a treated section selected to react with a chemical species;

a resistive heater thermally couplable to the treated section; and

first and second electrodes electrically coupled to the piezoelectric layer;

a driver circuit electrically coupled to the first and second electrodes and configured to actuate the cantilevered probe;

a sensing circuit electrically coupled to the first and second electrodes and configured to sense oscillation of the cantilevered probe;

a heater circuit electrically coupled to the resistive heater; and

a plurality of additional cantilevered probes arranged in an array together with the first cantilevered probe, each of the plurality of additional cantilevered probes comprising;

a piezoelectric layer; and

first and second electrodes electrically coupled to the piezoelectric layer;

wherein the first cantilevered probe is actuated when, through the first and second electrodes, a drive voltage is applied to the piezoelectric layer by the driver circuit, the actuated cantilevered probe generating a displacement signal transmitted to the sensing circuit, and wherein the piezoelectric layers of each of the cantilevered probes of the array are connected in series.

2. The sensor system of claim 1, wherein

each of the plurality of additional cantilevered probes comprises a resistive heater;

and

an electrical lead electrically coupled to the heater circuit and each of the resistive heaters of the plurality of additional cantilevered probes.

3. The sensor system of claim 1, wherein the resistive heater is formed as one piece with the cantilevered probe.

4. The sensor system of claim 1, further comprising a passivation layer disposed on the piezoelectric layer of the first cantilevered probe.

5. The sensor system of claim 1, wherein

at least two of the array of cantilevered probes having a treated section different from one another.

6. A method of determining the composition of a sample comprising:

providing a first cantilevered probe and a plurality of additional cantilevered probes arranged in an array together with the first cantilevered probe,

the first cantilevered probe comprising;

a piezoelectric layer;

a resistive heater;

a treated section;

a first electrode electrically coupled to the piezoelectric layer; and

a second electrode electrically coupled to the piezoelectric layer; and

each of the plurality of additional cantilevered probes comprising;

a piezoelectric layer; and

first and second electrodes electrically coupled to the piezoelectric layer;

wherein the piezoelectric layers of each of the cantilevered probes of the array are connected in series;

driving the first cantilevered probe by applying an excitation voltage to the piezoelectric layer;

sensing vibration of the first cantilevered probe by measuring a signal generated by the piezoelectric element;

exposing the treated section to a sample; and

after exposing the treated section to the sample, sensing vibration of the first cantilevered probe by measuring a signal generated by the piezoelectric element.

7. The method of claim 6 wherein exposing the treated section to a sample comprises exposing the treated section to a liquid sample.