HETEROSTRUCTURE SINGLE CRYSTAL SILICON PHOTOVOLTAICnSOLAR CELLS January 1-March 31,1978

摘要

The use of scanned laser (6330A) spot excitation of MIS cells has allowed estimation of grain boundary geometry effects on VOC and Isc of cells prepared on polycrystalline silicon substrates. Cells on polycrystalline material prepared by Czochralski and dendritic web growth methods have been studied. Photocurrent suppression, by grating boundary recombination mechanisms, of about 3% was estimated for excita¬tion at the laser wavelength for both materials. Details of total grain boundary length, width of the affected region and local strength of the suppression were different for the two cases. Bucking current density (assumed normal to the boundary walls cutting through the wafer) values were estimated to be 40 to 80% of those of the usual bucking current normal to the illuminated surface. Gold Schottky barrier and MIS cells on n-substrates exhibit barrier height and open circuit voltage sensitivity to details of the silicon etch preceding metallization or oxidation.