SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 23: Focus Session: Breakthroughs in wide-bandgap semiconductor laser diodes I
HL 23.1: Invited Talk
Wednesday, March 29, 2023, 09:30–10:00, POT 251
Vertical-cavity surface-emitting lasers -- this is the way — •Å. Haglund1, G. Cardinali2, L. Persson1, F. Hjort1, J. Enslin2, E. Torres1, C. Kuhn2, S. Graupeter2, M. Grigoletto2, M. A. Bergmann1, N. Prokop2, M. Guttmann2, L. Sulmoni2, N. Lobo Ploch3, M. Cobet2, T. Kolbe3, J. Gustavsson1, F. Nippert2, I. Häusler2, M. R. Wagner2, J. Ciers1, T. Wernicke2, and M. Kneisl2, 3 — 1Chalmers University of Technology, Göteborg, Sweden — 2Technische Universität Berlin, Berlin — 3FBH, Berlin
In recent years, there has been tremendous improvement in the performance of blue-emitting vertical-cavity surface-emitting lasers (VCSELs). Ultraviolet (UV)B (280-320 nm) and UVC (<280 nm) VCSELs have also been demonstrated, but so far only under optical pumping. All VCSELs require high reflectivity mirrors with an accurate cavity length control, but there is today no consensus on which is the best approach to realize this. We will summarize state of the art and then go into depth on our concept which is based upon using all-dielectric distributed Bragg reflectors where substrate removal is achieved by selective electrochemical etching. This approach has enabled the world's first UVB VCSEL at 310 nm. It also gives access to both sides of the cavity which allows for detuning postgrowth with drastically reduced lasing thresholds as well as an athermalized lasing wavelength. Thus, we believe that - this is the way - for nitride VCSELs. As a first step towards electrically injected UV VCSELs, we will demonstrate resonant cavity light emitting diodes with tunnel junctions.