Please kindly visit the official website of the Ministry of Foreign Affairs of the Republic of Turkey http://www.mfa.gov.tr/visa-information-for-foreigners.en.mfa  to search the visa requirements for Turkey. If it is needed, a formal invitation letter will be gladly e-mailed for the participants who had completed their registration process and for the residents who had scholarship.

Visa Information For Foreigners

As of April 17, 2013, electronic visa (e-Visa) replaces “sticker visa” which was issued at the border crossings. Applicants just need to log on to www.evisa.gov.tr , provide the requested information, (after the application is approved) make online payment and download their e-Visa. 
Please note that e-visa is only valid when the purpose of travel is tourism or commerce. Other purposes, such as work and study, require regular visa given by Embassies or Consulates. 
Passports should be valid at least six months longer than the expiry date of the requested visa. 
The term "official passports" covers diplomatic, service, special and official passports. 
Regardless of the visa regime applied towards the citizens of a country, the travel document holders of that country need to obtain visa from Turkish missions beforehand. 
Foreigners who will shoot a documentary film conduct a research or an archeological excavation should get a special permission from the Turkish authorities in advance.