Analysis of contamination, hydrogen emission, and surface temperature variations using real time spectroscopic ellipsometry during p/i interface formation in amorphous silicon p-i-n solar cells

The formation of p/i interfaces in hydrogenated amorphous silicon p-i-n solar cells prepared by plasma-enhanced chemical vapor deposition has been studied in detail using real time spectroscopic ellipsometry. With this technique, three effects have been successfully separated and quantified: (i) contaminant layer deposition at the p-layer surface with a sensitivity of +/- 0.1 A, (ii) thermal emission of bonded hydrogen from the p layer with a sensitivity of +/- 0.1 at. % (+/- 2 meV in optical gap), and (iii) surface temperature variations with a sensitivity of +/- 1 degrees C. The separation of these competing effects has yielded a better understanding of p/i interface formation and device optimization. (c) 1999 American Institute of Physics. [S0003-6951(99)02624-8].