Liquid Phase Epitaxy ​LPE is a high-temperature solution growth technique, in which a thin layer of the required material is deposited onto a suitable substrate.

Homoepitaxy is defined as growth of a layer of the same composition as the substrate, whereas heteroepitaxy is the growth of a layer of markedly different composition.

A suitable substrate material would have the same crystal structure as the layer, have as close a match in lattice parameter as possible, and be chemically compatible with the solution and the layer. LEP was established for III–V compound semiconductor lasers, LEDs, photodiodes, and solar cells. ​​