The purpose of a solar cell is to convert light energy to electrical energy.  Thus, the measurement called Light Beam Induced Current (LBIC) is of prime importance.  While a crude LBIC measurement involves just shining a white light on a solar cell and measuring the resultant current, Semilab’s measurement is considerably more complex and more valuable.  The Semilab measurement reveals the fine structure of variations in LBIC within a cell and makes the measurement at 4 discrete wavelengths of light, to show spectral response.

The Semilab LBIC measurement illuminates the solar cell with a single wavelength of laser light using small spot of light, 100μm in diameter.  The spot is then scanned over the entire cell, using a programmable step size in the raster scan.  The raster size is 2x10^Y mm, where Y can be any value from -4 to +6.  Then the same sequence is repeated using a different wavelength of light, until all the response from all wavelengths have been measured.  With the LBIC information, we can calculate Quantum Efficiency (QE) at each wavelength.  The system output includes maps of LBIC at each wavelength and maps of QE at each wavelength.