Abstract: The semiconductor light-emitting device includes an n-type semiconductor layer, a plurality of columnar semiconductors on the n-type semiconductor layer, a buried layer filling in a space between the columnar semiconductors, and a current suppression region suppressing a current. The columnar semiconductors has a hexagonal column and an active layer covering the hexagonal column. The hexagonal column has a hexagonal first surface and a second surface opposite to the first surface. The first surface of the columnar semiconductors faces the base layer. The second surface of the columnar semiconductors faces the current suppression region.

Abstract: An improved method for cleaning a group III-nitride-based semiconductor surface prior to depositing electrodes or growing additional layers of semiconductor. In a cleaning method according to the present invention, the surface of the semiconductor is brought into contact with an etchant solution that includes hydrofluoric acid. The etching step is preferably carried out at a HF concentration greater than 5% and at a temperature between 10 to 100.degree. C. in an inert atmosphere. The etchant solution may also include other acids. Group III-nitride semiconductor devices cleaned in this manner require lower driving voltages than devices cleaned with prior art methods.