12758
With carboxylic acid functionalized DWCNT TFTs , we obtained excellent gate modulation ( on / off ratio as high as 4000 ) with relatively high ON currents at a CNT areal density as low as 35 ng / cm ( 2 ) .
 Chemical: carboxylic acid
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: carboxylic acid