Thermal and Light Induced Infrared Blackening of ZnO Revisited: Overcoming the Language Border and Rediscovery of Fundamental Scientific Knowledge

A comprehensive and reliable view on the influence of UV light and heat on optical properties of ZnO shall be outlined mainly based on research conducted by scientists from Warsaw Pact countries throughout the 20th century. The problems of language barrier and loss of knowledge are being addressed. An insight into processes of photodesorption and photoadsorption of oxygen and other gas phase molecules leading to changes in charge carrier states is outlined. While desorption of surface adsorbates leads to increased number of conduction electrons and thus increased absorbance of infrared light, adsorption of electronegative gas phase molecules leads to quenching in fluorescence.