The specifics: a germanium wafer is spun at high speeds and subjected to various gases that encourage the growth of layers of semiconducting material such as gallium arsenide. (scientificamerican.com)
Photovoltaic devices use semiconducting material like silicon in a related way, with incoming photons knocking loose electrons to generate electricity. (scientificamerican.com)
Simply put, by employing less expensive semiconducting material thin - film solar cells would be cheaper to make, a fact born out by thin - film solar manufacturer First Solar's world - beating module that costs 73 cents per watt in 2011, albeit before the expense of installing it on the roof. (scientificamerican.com)