Low Cost Glass and Glass-Ceramic Substrates for Thin-Film Silicon Solar Cells

This report describes how Cornell University researchers developmed several low-cost and simple barrier layers and tested their effectiveness both analytically (by SIMS) and by evaluating the electrical characteristics of devices fabricated on barrier-coated substrates. Devices fabricated included both majority-carrier devices (thin-film transistors) and minority-carrier devices (p-i-n junction diodes simulating solar cells) using various deposition techniques including the chemical vapor deposition of polysilicon from silane at low pressures (at Cornell University) and from dichlorosilane at atmospheric pressure (cooperation with Neudeck at Perdue University). The structure of the films deposited was investigated by using TEM and X-ray analysis. The performance of the minority- and majority-carrier devices fabricated on barrier-coated glass ceramic substrates was found to be identical to devices fabricated on control substrates of oxidized silicon and fused silica.