8392
We report the direct measurement of the Dirac point , the Fermi level , and the work function of graphene by performing internal photoemission measurements on a graphene / SiO ( 2 ) / Si structure with a unique optical - cavity enhanced test structure .
 Chemical: graphene; Chemical: graphene; Chemical: SiO ( 2 ); Chemical: Si
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: graphene; Chemical: graphene; Chemical: SiO ( 2 ); Chemical: Si