Dresden 2017 – wissenschaftliches Programm
HL 25.18: Poster
Montag, 20. März 2017, 15:00–19:00, P2-OG2
Investigation of AlGaN multiple quantum wells for deep ultraviolet emission using temperature and excitation power density dependent photoluminescence spectroscopy — Christoph Reich, •Baran Avinc, Johannes Enslin, Norman Susilo, Christian Kuhn, Tim Wernicke, and Michael Kneissl — Technische Universität Berlin, Institute of Solid State Physics
Light emitting diodes in the deep UV spectral region have various interesting applications, e.g. gas sensing or water disinfection. However, the output power and performance of devices emitting in the UVC (200 nm - 280 nm) spectral region are poor compared to devices emitting at longer wavelenghts. This low external quantum efficiency in the UVC spectral region can be explained by the challenging carrier injection and lower internal quantum efficiency as well as a reduced light extraction due to a switching of the optical polarization from TE (transverse electric) to TM (transverse magnetic) for decreasing emission wavelengths. Using temperature and excitation power density dependent photoluminescence spectroscopy, we investigated the influence of the AlGaN-based multiple quantum well (QW) active region design on the internal quantum efficiency, the quantum confined Stark effect, and the radiative recombination processes. In a systematic study, the QW width as well as the aluminum contents in the QWs and barriers have been varied. The measured photoluminescence results will be compared with simulations based on k· p-perturbation theory including a discussion of the influence of the QW design on the optical polarization.