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We uncover that the sensitivity ( in terms of modulation in electrical conductivity ) of pristine graphene chemFETs is not necessarily intrinsic to graphene , but rather it is facilitated by external defects in the insulating substrate , which can modulate the electronic properties of graphene .
 Chemical: pristine graphene; Chemical: graphene; 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: pristine graphene; Chemical: graphene; Chemical: graphene