Optical Modulation Spectroscopy

Laboratory for Optical Spectroscopy of Nanostructures contains several setups suitable for performing photoreflectance (PR) and contactless electroreflectance (CER) measurements. They are set on Newport optical tables. The modulation is provided by the air capacitors (CER), or lasers (Ar+, Nd: YAG, He-Ne), with the beam chopped by mechanical choppers (PR). The detection systems consists of monochromators (Jobin-Yvon, Carl Zeiss Jena) with various detectors (photodiodes and photomultipliers) and the signal recorded by the lock-in amplifiers (Stanford Research and EG&G), enabling the measurements in the spectral range from 250 nm up to 5 µm. The control of the experiment temperature is possible due to the application of liquid helium(nitrogen) cryostats (4.2 (77) K up to 300 K) or closed cycle helium coolers (10-400 K). The PR measurements in the function of the pressure up to 1.8 GPa may be performed using the hydrostatic pressure optical cell. The studies in the magnetic fields up to 5 T are also possible with the Oxford Instruments optical cryostat with superconducting magnet.

Representative papers

Optical properties of GaAsBi/GaAs quantum wells: Photoreflectance, photoluminescence and time-resolved photoluminescence study
J. Kopaczek, W. M. Linhart, M. Baranowski, R. D. Richards, F. Bastiman, J. P. R. David, R. Kudrawiec
Semicond. Sci. Technol. 30, 094005 (2015)
Electronic band structure of compressively strained Ge1-xSnx with x<0.11 studied by contactless electroreflectance
K. Żelazna, M. P. Polak, P. Scharoch, J. Serafinczuk, M. Gladysiewicz, J. Misiewicz, J. Dekoster, R. Kudrawiec
Appl. Phys. Lett. 106, 142102 (2015)
Photoreflectance spectroscopy of GaInSbBi and AlGaSbBi quaternary alloys
J. Kopaczek, M. K. Rajpalke, W. M. Linhart, T. S. Jones, M. J. Ashwin, R. Kudrawiec, T. D. Veal
Appl. Phys. Lett. 105, 112102 (2014)
Photomodulation spectroscopy applied to low-dimensional semiconductor structures
J. Misiewicz, G. Sęk, R. Kudrawiec, K. Ryczko, D. Gollub, J.P. Reithmaier, A. Forchel
Microelectronics Journal 34, 351 (2003)
Semiconductor heterostructures and device structures investigated by photoreflectance spectroscopy
J. Misiewicz, P. Sitarek, G. Sęk, R. Kudrawiec
Materials Science 21, 263 (2003)