Crystalline silicon is used as the semiconductor in many solar cells but it is expensive. Layered semiconductors such as indium selenide (InSe) and gallium selenide (GaSe) of the chalcogenide chemical family are promising candidates for solar cells as they show ideal surface and interface properties and can also reduce the costs 10-fold. To date, however, there have been problems making thin films of these layered chalcogenides and they have exhibited unfavourable properties. This has prohibited the use of these materials in solar cells.