Methods of forming layers comprising epitaxial silicon, and methods of forming field effect transistors are disclosed. A method of forming a layer comprising epitaxial silicon includes etching an opening into a silicate glass-comprising material received over a monocrystalline material. The etching is conducted to the monocrystalline material effective to expose the monocrystalline material at a base of the opening. A silicon-comprising layer is epitaxially grown within the opening from the monocrystalline material exposed at the base of the opening. The silicate glass-comprising material is etched from the substrate effective to leave a free-standing projection of the epitaxially grown silicon-comprising layer projecting from the monocrystalline material which was at the base of the opening. Other implementations and aspects are contemplated.