18819
This low - temperature ( T = 120 degrees C ) route to conformal deposition of crystalline Fe3O4 or alpha - Fe2O3 thin films is determined by the choice of oxygen source selected for the second surface half - reaction .
 Chemical: Fe3O4; Chemical: alpha - Fe2O3; Chemical: oxygen
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: Fe3O4; Chemical: alpha - Fe2O3; Chemical: oxygen