High-density and optical non-linearity effects in epitaxially grown ZnTe layers
Article first published online: 14 SEP 2004
Copyright © 1994 John Wiley & Sons, Ltd.
Advanced Materials for Optics and Electronics
Volume 3, Issue 1-6, pages 33–39, January 1994
How to Cite
Wagner, H. P., Festner, S., Stanzl, H., Kudlek, G. and Presser, N. (1994), High-density and optical non-linearity effects in epitaxially grown ZnTe layers. Adv. Mater. Opt. Electron., 3: 33–39. doi: 10.1002/amo.860030106
- Issue published online: 14 SEP 2004
- Article first published online: 14 SEP 2004
- High-density luminescence;
- Non-linear transmission;
- Metal-organic vapour phase epitaxy;
- Inelastic exciton scattering;
- Electron–hole plasma;
- Pump-and-probe method;
- Exciton screening;
- Band gap renormalization
We investigated the high-density luminescence and non-linear transmission of ZnTe layers grown by metal-organic vapour phase epitaxy (MOVPE). For the high-density luminescence we compared ZnTe layers on (001) GaAs substrate with free-standing ZnTe layers of equal thickness. At high excitation intensities a strong luminescence P band appears a few meV below the free exciton energy which is assigned to resonant exciton-scattering processes. A second strong luminescence N band occurs only in free-standing layers. It shows a remarkable red shift with increasing intensity and becomes the dominant emission for an excitation intensity Iexc > 1.5 MW cm−2. This lower-energy band was interpreted as electron–hole plasma recombination.
The optical non-linearity of thin ZnTe layers in the excitonic region was investigated by pump-and-probe experiments at 2 K and room temperature (RT). For these experiments we used two different pump energies, one above (at 2 K and RT) and one below (at 2 K) the band gap energy. In all cases a red shift and a large non-linear decrease in the excitonic absorption with increasing pump intensity was observed. The experimental results can be explained by many-body effects of exciton screening.