28812
Optical transmission spectra reveals the existence of considerable deep band gaps of up to 70 % and steep band edges of up to 6 % / nm in the [ 111 ] directions of the 3DOM silica samples .
 Chemical: silica
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: silica