2020, Schlykow, Viktoria, Manganelli, Costanza Lucia, Römer, Friedhard, Clausen, Caterina, Augel, Lion, Schulze, Jörg, Katzer, Jens, Schubert, Michael Andreas, Witzigmann, Bernd, Schroeder, Thomas, Capellini, Giovanni, Fischer, Inga Anita

We report on photodetection in deep subwavelength Ge(Sn) nano-islands on Si nano-pillar substrates, in which self-aligned nano-antennas in the Al contact metal are used to enhance light absorption by means of local surface plasmon resonances. The impact of parameters such as substrate doping and device geometry on the measured responsivities are investigated and our experimental results are supported by simulations of the three-dimensional distribution of the electromagnetic fields. Comparatively high optical responsivities of about 0.1 A W-1 are observed as a consequence of the excitation of localized surface plasmons, making our nano-island photodetectors interesting for applications in which size reduction is essential. © 2020 The Author(s). Published by IOP Publishing Ltd.

2020, Amano, Hiroshi, Collazo, Ramón, De Santi, Carlo, Einfeldt, Sven, Funato, Mitsuru, Glaab, Johannes, Hagedorn, Sylvia, Hirano, Akira, Hirayama, Hideki, Ishii, Ryota, Kashima, Yukio, Kawakami, Yoichi, Kirste, Ronny, Kneissl, Michael, Martin, Robert, Mehnke, Frank, Meneghini, Matteo, Ougazzaden, Abdallah, Parbrook, Peter J., Rajan, Siddharth, Reddy, Pramod, Römer, Friedhard, Friedhard, Jan, Sarkar, Biplab, Scholz, Ferdinand, Schowalter, Leo J, Shields, Philip, Sitar, Zlatko, Sulmoni, Luca, Wang, Tao, Wernicke, Tim, Weyers, Markus, Witzigmann, Bernd, Wu, Yuh-Renn, Wunderer, Thomas, Zhang, Yuewei

Solid state UV emitters have many advantages over conventional UV sources. The (Al,In,Ga)N material system is best suited to produce LEDs and laser diodes from 400 nm down to 210 nm - due to its large and tuneable direct band gap, n- and p-doping capability up to the largest bandgap material AlN and a growth and fabrication technology compatible with the current visible InGaN-based LED production. However AlGaN based UV-emitters still suffer from numerous challenges compared to their visible counterparts that become most obvious by consideration of their light output power, operation voltage and long term stability. Most of these challenges are related to the large bandgap of the materials. However, the development since the first realization of UV electroluminescence in the 1970s shows that an improvement in understanding and technology allows the performance of UV emitters to be pushed far beyond the current state. One example is the very recent realization of edge emitting laser diodes emitting in the UVC at 271.8 nm and in the UVB spectral range at 298 nm. This roadmap summarizes the current state of the art for the most important aspects of UV emitters, their challenges and provides an outlook for future developments. © 2020 IOP Publishing Ltd.