THz and Time-Resolved Optical Spectroscopy of Buried Interfaces

Summary

The main focus of this project is the experimental study of the carrier dynamics at buried interfaces in semiconductor systems. We will employ optical pump-white-light probe, optical pump-Thz probe spectroscopy and time-resolved luminescence to study the initial charge transfer through the interface as well as the formation and decay dynamics of charge-transfer excitons. As a new aspect we will also investigate the coherent dynamics of charge-transfer excitons performing four-wave-mixing experiments on spatially indirect transitions. In the second phase of the collaborative research center we will intensify our investigations to reveal correlations between the structural quality of the interface and the carrier dynamics on the different time-scales. In addition, we will continue to study how strong transient THz fields modify the initial carrier dynamics at buried interfaces.

The samples will be grown in project A1 (Stolz) and will be structurally characterized in project A5 (Volz). The analysis of the experimental data will be performed in close cooperation with B4 (SW Koch).

Project-related publications

1. L. Rost, S. Gies, M. Stein, C. Fuchs, S. Nau, P. Kükelhan, K. Volz, W. Stolz, M. Koch, W. Heimbrodt
   Correlation of optical properties and interface morphology in type-II semiconductor heterostructures
   J. Phys. Condens. Matter 31, 014001 (2019).
2. M. Stein, C. Lammers, P.-H. Richter, C. Fuchs, W. Stolz, M. Koch, O. Vänskä, M.J. Weseloh, M. Kira, S.W. Koch
   Dynamics of charge-transfer excitons in type-II semiconductor heterostructures
   Phys. Rev. B 97, 125306 (2018).
3. M. Stein, C. Lammers, M.J. Drexler, C. Fuchs, W. Stolz, M. Koch
   Enhanced absorption by linewidth narrowing in optically excited type-II semiconductor heterostructures
   Phys. Rev. Lett. 121, 017401 (2018).
4. W.-R. Hannes, A. Trautmann, M. Stein, F. Schäfer, M. Koch, T. Meier
   Strongly nonresonant four-wave mixing in semiconductors
   Phys. Rev. B 101, 075203 (2020).
5. I. Meyenburg, N. Hofeditz, R. Ruess, M. Rudolph, D. Schlettwein, W. Heimbrodt
   Optical determination of charge transfer times from indoline dyes to ZnO in solid state dye-sensitized solar cells
   AIP Adv. 8, 055218 (2018).
6. L.M. Schneider, S. Lippert, J. Kuhnert, O. Ajayi, D. Renaud, S. Firoozabadi, Q. Ngo, R. Guo, Y.D. Kim, W. Heimbrodt, J.C. Hone, A. Rahimi-Iman
   The influence of the environment on monolayer tungsten diselenide photoluminescence
   Nano-Struct. Nano-Objects 15, 84 (2018).