SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 23: Focus Session: Breakthroughs in wide-bandgap semiconductor laser diodes I

HL 23.4: Talk

Wednesday, March 29, 2023, 11:30–11:45, POT 251

Time-dependent intensity and wavelength dynamics of blue laser diodes with wide quantum wells — •Jannina Tepaß¹, Lukas Uhlig¹, Mateusz Hajdel², Grzegorz Muziol², and Ulrich Theodor Schwarz¹ — ¹Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany — ²Institute of High Pressure Physics, Polish Academy of Sciences, Poland

In this study, thick quantum wells with two different thicknesses of 10.4 nm and 25 nm are analyzed. The very low overlap of the electron and hole wavefunction in such QWs due to the quantum confined Stark effect would indicate inefficient devices. However, it has been shown that thick QWs can be more effective and achieve high optical gain. This can be explained by the electric field screening that leads to a high overlap of the excited electron and hole states, which enable lasing. In this work, a pulsed electrical excitation scheme is used in which carrier injection at forward voltage is largely separated from carrier recombination at zero or reverse voltage. Due to this effect, the interplay between the piezoelectric field and the built-in potential on the charge carrier recombination in dependence on an external bias voltage can be observed. In particular, a sharp increase in the radiative recombination rate after the trailing edge of the driving pulse is observed, as well as a wavelength shift.