A light-emitting device having one or more diamond layers integrated therein and methods for forming a light-emitting device with integrated diamond layers. The diamond is grown either directly on the semiconductor material comprising the light-emitting structure, on a nucleation layer deposited on the semiconductor material, or on a dielectric layer deposited on the semiconductor material before growth of the diamond layer. The device can include a trench or thermal shunt formed in the substrate on the backside of the device, or can include a heat sink to provide additional thermal management.