Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent optical element (e.g., a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection.

Abstract: A semiconductor light emitting heterostructure device is disclosed. The device comprises an n-type GaAs substrate, a first n-type laeyr of AlGaAs adjacent to the substrate, a second p-type light emitting AlGaAs layer adjacent to the first layer, and a third p-type AlGaAs layer suitable for bonding to an aluminum contact. The device starts with an n-type substrate which is more readily available and has a p-side up configuration which is more suitable for bonding to an aluminum contact.