Portable radiometer: a novel technique for in situ band gap measurements

Portable radiometers are commonly used in remote sensing applications for studying vegetation, soil, minerals, etc. However, we propose and demonstrate, for the first time, the applicability of this radiometer for high-resolution in situ band gap measurements of materials. The excitation source can be any white light source such as sun or tungsten halogen lamp. The flexibility in sample size and relative ease of varying temperature during measurements add to the advantages of using a portable radiometer for investigating new materials. Accurate measurements were made on standard samples of silicon, germanium, and gallium antimonide to demonstrate the feasibility of this technique.