Theoretical Considerations on Current Spreading in GaN-Based Light Emitting Diodes Fabricated with Top-Emission Geometry

We report theoretical considerations regarding current spreading in GaN-based light emitting diodes (LEDs) fabricated with top-emission geometry, in which sheet resistances of both top transparent electrodes and n-layers are taken into consideration, whereas vertical resistance associated with the p-contact and the p-layer is neglected. The current spreading length is inversely proportional to the injected current density , namely, , and can be increased as the sheet resistances of either the transparent electrode or the n-layer are reduced. The effects of the material parameters (sheet resistances of transparent electrode and n-layer) on current spreading and hence the LED performance are discussed.