Atomic force microscopy apparatus, methods, and applications
AssigneeCornell University
InventorsJohn Marohn, Sarah Nathan, Ryan Dwyer
Life of this patent
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Abstract
Atomic force microscopy apparatus and method that enable observing charge generation transients with nanometer spatial resolution and nanosecond to picosecond time resolution, the timescale relevant for studying photo-generated charges in the world's highest efficiency photovoltaic films. The AFM apparatus includes an AFM, a light source for illumination of a sample operatively coupled to the AFM, a voltage source operatively coupled to the AFM, and a control circuitry operatively coupled to the light source and the voltage source. The AFM apparatus improves the time resolution and enables rapid acquisition of photocapacitance transients in a wide array of solar-energy-harvesting materials.
Claims20
An atomic force microscope (AFM) apparatus, comprising:
- a cantilever having a tip at a distal end;
- a driving element arranged to control movement of the cantilever;
- a first light source directed toward an AFM sample disposed adjacent a tip of the cantilever;
- a second light source directed toward the tip of the cantilever;
- a photodetector disposed to receive incident light from the second light source reflected from the tip of the cantilever and to output a signal relating to at least one of a position of the tip of the cantilever and movement of the tip of the cantilever;
- a voltage source configured to provide a pulsed voltage to the cantilever and to the first light source to cause the first light source to output a light pulse toward an AFM sample;
- and
- a control circuit operatively coupled at least to the first light source and the voltage source.
A system for measuring the time-evolution of charge or polarization induced by light in a sample, comprising:
- a first laser positioned to illuminate a sample;
- an atomic force microscope (AFM) having:
- a controller,
- a cantilever with a tip located at a height above the sample;
- a drive mechanism operatively coupling the cantilever and the controller;
- a second laser configured to emit light at the tip of the cantilever;
- and
- a photodetector coupled to the controller;
- a pulse generator operatively coupled to provide a first pulsed voltage to the first laser to drive the first laser to illuminate the sample and to provide a second pulsed voltage to the cantilever to generate a voltage at the tip of the cantilever;
- and
- and
- a timing component configured to trigger the pulse generator.
Dependencies are inferred from the claim text.