Bergmann, Michael A.Enslin, JohannesHjort, FilipWernicke, TimKneissl, MichaelHaglund, Åsa2020-05-282020-05-282020-03-240003-6951https://depositonce.tu-berlin.de/handle/11303/11241http://dx.doi.org/10.14279/depositonce-10129We demonstrate a thin-film flip-chip (TFFC) light-emitting diode (LED) emitting in the ultraviolet B (UVB) at 311 nm, where substrate removal has been achieved by electrochemical etching of a sacrificial Al0.37Ga0.63N layer. The electroluminescence spectrum of the TFFC LED corresponds well to the as-grown LED structure, showing no sign of degradation of structural and optical properties by electrochemical etching. This is achieved by a proper epitaxial design of the sacrificial layer and the etch stop layers in relation to the LED structure and the electrochemical etch conditions. Enabling a TFFC UV LED is an important step toward improving the light extraction efficiency that limits the power conversion efficiency in AlGaN-based LEDs.en530 Physikultraviolet lightetchingelectroluminescenceepitaxylight emitting diodeselectrochemistryflip chipnitridesthin film devicessemiconductorsArticle1077-3118