Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 33: Poster Session III

HL 33.13: Poster

Mittwoch, 14. März 2018, 17:30–19:30, Poster F

Dose and bias dependend cathodoluminescence efficiency of InGaN/GaN MQWs — •Hendrik Spende¹, Johannes Ledig^1,2, Christoph Margenfeld¹, Angelina Vogt¹, Sönke Fündling¹, Hergo-Heinrich Wehmann¹, Tobias Voss¹, and Andreas Waag¹ — ¹Institute of Semiconductor Technology and Laboratory for Emerging Nanometrology, Braunschweig University of Technology, 38092 Braunschweig — ²Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany

Cathodoluminescence (CL) inside a scanning electron microscope (SEM) is a powerful tool to probe optical properties of semiconductor microstructures with high spatial resolution. The primary electron probe is scattered and the generated e-h pairs undergo sample related drift and diffusion. Therefore, the radiative recombination inside the material is spatially inhomogeneous and although resolving local electro-optical properties a quantitative interpretation is difficult.

This work aims at understanding the underlying mechanisms to pave the way for a quantiative interpretation. Dedicated MOVPE grown InGaN/GaN test samples were analyzed by CL at room and LN2 temperatures inside a SEM. Each sample contains MQWs emitting at different wavelengths stacked in growth direction. Thus, spectra taken with different electron beam energies provide depth dependent information on the recombination from different MQWs. We observe unexpected time and temperature dependent changes in the CL emission of the samples which suggest electron beam induced changes in carrier dynamics inside the MQW region which is verified by voltage biased CL.