17808
The resistive switching is controlled by the formation and rupture of an Ag nanoisland chain on the surface along the Na - doped ZnO nanowire .
 Chemical: Ag; Chemical: Na; Chemical: ZnO
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: Ag; Chemical: Na; Chemical: ZnO