RAPID ANALYSIS OF BUFFER LAYER THICKNESS FOR THIN FILM SOLAR CELLS

摘要

A method and apparatus for measuring thickness of a film in a solar cell provides for directing light emitted at multiple emission wavelengths, to a surface of the solar cell. Each emission results in the generation of a responsive photo current. The photo currents are read by a current meter having one contact coupled to a surface of the solar cell and another contact coupled to another surface. The currents associated with each of the different light emissions are identified and the thickness of a film in the solar cell is calculated based on the two currents or associated quantum efficiencies, and associated absorption coefficients. In one embodiment, the film thickness is the thickness of a CdS or other buffer film in a thin film solar cell.

主权项

1. A method for measuring thickness of a solar cell film, said method comprising:
providing a solar cell that includes a buffer layer with a wavelength dependent absorption coefficient; generating light having a plurality of emission wavelengths; exposing said solar cell to at least two wavelengths of said light; measuring photovoltaic currents generated in said solar cell responsive to said exposing, for each of said wavelengths of said light; mathematically calculating thickness of said buffer layer based on said measured photovoltaic currents; and delivering an output signal of said calculated thickness to a further device.