Patent ID: 7906972

Claim:
A method of inline inspection of photovoltaic material for electrical anomalies without removing samples from the material, the method comprising the steps of: applying a first light, called a probe source, to a location of the photovoltaic material, where the probe source is applied at a probe energy sufficient to emit photoelectrons from a conduction band of the photovoltaic material into a vacuum environment, but the probe energy is insufficient to substantially excite electrons from a valence band of the photovoltaic material into the vacuum environment, selectively simultaneously applying a second light, called a pump source, to the location of the photovoltaic material, where the pump source is applied at a pump energy sufficient to excite photoelectrons from the valence band of the photovoltaic material to the conduction band, but the pump energy is insufficient to substantially emit photoelectrons from the conduction band of the photovoltaic material into the vacuum environment, sensing the photoelectrons that are excited into the vacuum environment to measure a current, and interpreting fluctuations in the current as electrical anomalies.