6164
Assigning of the carbon nanotube type was done by a combination of high-resolution transmission electron microscopy ( HRTEM ) , Raman spectroscopy , and density functional theory ( DFT ) calculations .
 Raman
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Raman