Project B7: Interface-Dominated Semiconductor Laser Structures

Principle Investigators: Dr. Wolfgang Stolz, Prof. Dr. Stephan W. Koch (Marburg, WZMW & Dept. of Physics)

Summary

This project is dedicated to the design, growth, characterization, and analysis of novel interface-dominated semiconductor laser structures with spatially indirect barrier/quantum well combinations. This type-II band alignment allows for added flexibility in choosing the emission wave-length and the minimization of the intrinsic losses while maintaining good gain properties.
The first realization and analysis of optimized edge-emitting as well as surface-emitting type-II-laser structures for an emission wavelength around 1.2 μm have verified the anticipated high values of material gain and differential efficiency. At present, the activities are concentrating on type-II-designs for the emission wavelength ranges 1.25 μm to 1.35 μm as well as 1.5 μm to 1.65 μm. Based on the gained experience with the modelling, growth, characterization, and optimization of the relatively complicated type-II heterostructures, the main goal will be to realize systems with comparable gain but reduced intrinsic losses in comparison to the more established direct-gap compounds with type-I-band alignment used for lasers in these spectral ranges. At a later stage, the studies will be expanded to cover emitters in the regime > 2 μm.
This project will benefit from detailed experiment/theory-comparisons allowing for systematic investigations of the structural influence of the real potential profile on the gain as well as on spontaneous and nonradiative losses (Auger, inter-valence band absorption). In particular, the detailed analysis of the charge transfer dynamics under high carrier density excitation will form the basis also for mode-locked laser operation in these novel interface-dominated laser structures with type-II-band alignment.

Project-Related Publications

1. F. Zhang, C. Möller, M. Koch, S.W. Koch, A. Rahimi-Iman, W. Stolz
   Impact of detuning on the performance of semiconductor disc lasers
   Appl. Phys. B 123, 291 (2017).
2. I. Kilen, S.W. Koch, J. Hader, J.V. Moloney
   Mode-locking in vertical external-cavity surfaceemitting lasers with type-II quantum-well configurations
   Appl. Phys. Lett. 114, 252102 (2019).
3. P. Kükelhan, A. Beyer, C. Fuchs, M.J. Weseloh, S.W. Koch, W. Stolz, K. Volz
   Atomic structure of “W”-type quantum well heterostructures investigated by aberration-corrected STEM
   J. Microscopy 268, 259 (2017).
4. J.O. Oelerich, M.J. Weseloh, K. Volz, S.W. Koch
   Ab-initio calculation of band alignments for opto-electronic simulations
   AIP Adv. 9, 055328 (2019).
5. C. Fuchs, A. Brüggemann, M.J. Weseloh, C. Berger, C. Möller, S. Reinhard, J. Hader, J.V. Moloney, A. Bäumner, S.W. Koch, W. Stolz
   High-temperature operation of electrical injection type-II (GaIn)As/Ga(AsSb)/(GaIn)As “W”-quantum well lasers emitting at 1.3 μm
   Sci. Rep. 8, 1422 (2018).