Architecture of worlds fairs. paper of about 1800 words topic is Dubai EXPO 2020.

Architecture of worlds fairs. 

paper of about 1800 words topic is Dubai EXPO 2020.

The difficulty obviously is that it hasn't happened yet, so there's no scholarly material on it, mostly promotional material. You'll have to look closely at the sources and see if they are over-promising for the designs.

Within the general topic, you probably want to pick a focus. One direction would be to look at the master plan in relation to Dubai as a whole. The other would be to look at the national pavilions.