Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: Poster Session III

HL 33.6: Poster

Wednesday, March 14, 2018, 17:30–19:30, Poster F

Polarisation resolved PL-studies of thin AlBGaN-layers — •Natja Steiger¹, Sebastian Bauer¹, Markéta Zíková², Oliver Rettig³, Anja Ipsen¹, Yueliang Li⁴, Johannes Biskupek⁴, Ute Kaiser⁴, Ferdinand Scholz³, and Klaus Thonke¹ — ¹Institute of Quantum Matter/Semiconductor Physics Group, Ulm University, Ulm — ²The Czech Academy of Sciences, Prague — ³Institute of Optoelectronics, Ulm University, Ulm — ⁴Electron Microscopy Group of Materials Science, Ulm University, Ulm

We try to incorporate small amounts of boron into AlGaN to reduce the lattice mismatch to AlN. This enables strain management in the material system and should help to reduce the quantum confined Stark effect in quantum well structures, hence increasing the external quantum efficiencies of UV-LEDs. However, strain reduction can also have negative impact. By inverting the valence band order and thus switching the emission from TE to TM Mode. In the ternary compound AlGaN, this polarisation switching occurs at a specific composition, which is strongly strain dependent. For high Al content, for which the TM-polarisation is predominant, higher strain enhances TE polarisation. To study the influence of boron on strain and polarisation, mainly optical spectroscopy and X-Ray diffractometry were used, alongside with other characterisation methods. Even for reduced strain, enhanced TE polarisation was observed for boron containing samples.