Amorphous germanium waveguides for spectroscopic sensing and data communication applications

A method of forming amorphous Ge on a substrate, the method comprising:

• performing electron-beam evaporation of a starting material comprising polycrystalline Ge, until a layer of amorphous Ge is formed on a substrate;
• wherein:
• the starting material has a purity of at least 99.00%;
• the evaporation is performed in a vacuum chamber having a pressure not greater than 1×10−5 Torr;
• immediately prior to evaporation, the temperatures of the starting material and substrate are not greater than 30° C.;
• the evaporation is performed using an electron-beam current of at least 30 mA;
• and
• at the conclusion of the evaporation, the layer has a thickness of at least 50 nm and a purity of at least 90% Ge.