IR transmission spectra of 1n203 microcrystals and thin films in the range 300 - 700 cm-1 were studied. Results on band shifts support the idea that bands in microcrystals spectra correspond to surface polaritons. Anomalous clumping effects and different behavior with respect to charge carrier localization at low and high frequency bands are presented.
"Study Of Surface Polaritons And Bulk Modes Activity In In2O3 By IR Spectroscopy", Proc. SPIE 1038, 6th Mtg in Israel on Optical Engineering, (5 July 1989); doi: 10.1117/12.951080; https://doi.org/10.1117/12.951080