21320
Correlations between the graphene films grown and prevalent species in the equilibrium gas phase revealed that deposition conditions associated with a high acetylene equilibrium concentration lead to good quality graphene deposition , and conditions that stabilize large hydrocarbon molecules in the gas phase result in films with multiple defects .
 graphene, acetylene, graphene, hydrocarbon
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 graphene, acetylene, graphene, hydrocarbon