9071
A combination of scanning transmission electron microscopy , electron energy loss spectroscopy , and ab initio calculations reveal striking electronic structure differences between two distinct single substitutional Si defect geometries in graphene .
 Chemical: Si; Chemical: graphene
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: Si; Chemical: graphene