Evaluating the Band Gaps of Semiconductors by Cataluminescence.

A rapid and efficient methodology for the evaluation of band gaps of semiconductors is highly desirable to analyze and assess the intrinsic properties and extending application scopes of semiconductor materials. Here, the negative correlation of the cataluminescence (CTL) signal in the presence of H2S and the band gap of Aurivillius-type perovskite oxide Bi4+nFenTi3O12+3n (n = 1-4) was confirmed, where the H2S-induced CTL signal acts as a probe to evaluate the band gaps of semiconductor materials. The related mechanism shows that the thermal energy obtained by heating makes the electrons in the valence band more easily excite into the conduction band of a narrower band gap material and further promotes electron transfer between the gaseous compounds and semiconductor materials, causing acceleration of the catalytic oxide process. In addition, the extensibility was further verified by exploring the layered perovskite containing other insertion structures, including Bi4+nConTi3O12+3n (n = 1-4), Bi5NiTi3O15, and Bi5MnTi3O15, which was also consistent with the results characterized by UV diffuse reflectance spectroscopy. The established CTL probe for band gap evaluation shows rapid response, is simple to operate, and is of low cost, which is expected to become an innovative alternative to the conventional band gap assessment approach.