DISLOCATION FREE SEMICONDUCTOR NANOSTRUCTURES GROWN BY PULSE LASER DEPOSITION WITH NO SEEDING OR CATALYST

摘要

There is a method for forming a semiconductor nanostructure on a substrate. The method includes placing (1300) a substrate (105) and a semiconductor material (110) in a pulsed laser deposition chamber (115); selecting (1302) parameters including a fluence of a laser beam (120), a pressure P inside the chamber (115), a temperature T of the substrate (105), a distance d between the semiconductor material (110) and the substrate (105), and a gas molecule diameter a₀ of a gas (113) to be placed inside the chamber (115) so that conditions for a Stranski-Krastanov nucleation are created; and applying (1304) the laser beam (120) with the selected fluence to the semiconductor material (110) to form a plume of the semiconductor material (110). The selected parameters determine the formation, from the plume, of (1) a nanolayer (307) that covers the substrate (105), (2) a polycrystalline wetting layer (309) over the nanolayer (307), and (3) a single-crystal nanofeature (315) over the polycrystalline wetting layer (309), and the single-crystal nanofeature (315) is grown free of any catalyst or seeding layer.