I have an application page and I don't want master page. Is it possible in SharePoint 2013?
Application Pages in SharePoint are (almost) pure ASP.NET pages, so if you don't want to use a master page, then just leave out the MasterPageFile attribute in the Page element
By default, an Application Page item references the master page of the site that you are using to debug your project. That page is named
v4.master and you can find it listed in the Master Page Gallery of the SharePoint site.
You can explicitly change which master page is used by the application page by setting the MasterPageFile attribute of the application Page element. (For example: