27132
The functional heterostructures are fabricated by layer - by - layer , template - directed , electrochemical synthesis in porous anodic aluminum oxide membranes to produce high density arrays of electronically autonomous , nanostructured , corrosion resistant , photoactive units ( ~ 10 ( 9 ) - 10 ( 10 ) PAHs per cm ( 2 ) ) .
 Chemical: aluminum oxide
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: aluminum oxide