Differential sensor measurement methods and structures

A structure comprising:

• a first semiconductor nanosensor functionalized with a detector species, the first semiconductor nanosensor comprising a first input pad electrically connected to a first end of the first semiconductor nanosensor and a first detection pad electrically connected to a second end of the first semiconductor nanosensor opposite the first end;
• a second semiconductor nanosensor functionalized with a detector species and in electrical communication with the first semiconductor nanosensor, the second semiconductor sensor comprising a second input pad electrically connected to a first end of the second semiconductor nanosensor and a second detection pad electrically connected to a second end of the second semiconductor nanosensor opposite the first end;
• and
• a phase shifter electrically coupled with the first input pad of the first semiconductor nanosensor, the second input pad of the second semiconductor nanosensor, and a voltage source, wherein the phase shifter is configured to produce a first signal that is applied to the first input pad and a second signal having a phase that is shifted in phase by 180° relative to the first signal that is applied to the second input pad;
• wherein the first semiconductor nanosensor and the second semiconductor nanosensor are configured to output a differential electrical property between the first semiconductor nanosensor and the second semiconductor nanosensor when exposed to a sample comprising an analyte,
• wherein the first and second semiconductor nanosensors comprise one or more nanowires that are functionalized with the detector species and the nanowires have a cross-sectional dimension of less than or equal to about 150 nm;
• and
• wherein the nanowires of the first and the second semiconductor nanosensor include an aluminum oxide coating and a thickness of the aluminum oxide coating on the nanowires of the first semiconductor nanosensor is greater than a thickness of the aluminum oxide coating on the nanowires of the second semiconductor nanosensor.