Transistors, and methods of manufacturing the transistors, include graphene and a material converted from graphene. The transistor may include a channel layer including graphene and a gate insulating layer including a material converted from graphene. The material converted from the graphene may be fluorinated graphene. The channel layer may include a patterned graphene region. The patterned graphene region may be defined by a region converted from graphene. A gate of the transistor may include graphene.