Patent ID: 7888686
Filing Date: 2011-02-15
Classification: H05B

Abstract:
1. A light emitting device comprising: a substrate; an active layer structure supported on the substrate including at least a first active layer with a concentration of luminescent centers for emitting light at a first wavelength; a set of electrodes for applying an electric field to the active layer structure including an upper transparent electrode and a second base electrode; a metal electrical contact electrically connected to the transparent electrode for applying the electric field thereto; a field oxide region below the electrical contact and below a covered section of the active layer structure, which is below the electrical contact, for minimizing current injection into the covered section, thereby maximizing current flow in the active layer structure adjacent to the covered section; wherein the active layer structure comprises a first buffer layer comprising a wide bandgap semiconductor or dielectric material adjacent to the first active layer; and wherein the first buffer layer has a thickness, whereby electrons gains sufficient energy from the electric field when passing through the first buffer layer to excite the luminescent centers in the first active layer via impact ionization or impact excitation at a sufficient excitation energy to emit light at the first wavelength.