High‐density effects, stimulated emission, and electrooptical properties of ZnCdSe/ZnSe single quantum wells and laser diodes

Abstract

Dedicated to Professor Dr. K. W. BOER on the occasion of his 70th birthday In 11-VI material based laser diode structures, the role of excitonic processes for stimulated emission is still rather controversially discussed. In this paper, the manifestation of biexciton recombination in high-density luminescence of ZnCdSe/ZnSe quantum wells is investigated by intensity-and polarization-dependent spectroscopy. In spite of their evidence in such spectra, their contribution to stimulated emission in laser diodcs with moderately confining wells is not confirmed, instead, indication of strong Coulomb correlation is given when using the new technique of pump-and-probe excitation spectroscopy. A strong electrooptic effect yielding saturation is found in laser diodes exactly at their lasing wavelength thus being promising candidates for integrated laser-modulation devices.

Automated numerical characterization of dilute semiconductors per comparison with luminescence

“…Note that, in spite of its success to accurately explain experiments such as both single beam and nonlinear pump-probe photoluminescence (Michler et al 1998), as well as being a powerful tool to design optical devices and solar cells (Aeberhard 2011). Nonequilibrium Green's Functions (NEGF) techniques that include Photon Green's functions mentioned above and semiconductor Bloch equations, can be applied to both intersubband (Pereira 2011(Pereira , 2016Pereira and Faragai 2014) and interband transitions (Pereira et al 1994;Grempel et al 1996), but usually requires intensive numerical methods. Therefore, in this project, we did not fully calculate the dephasing attributed to electron-phonon, electron-impurity and electron-alloy disorder scattering and that leads to measured s-shape-like features in dilute semiconductor samples (Imhof et al 2010;Kesaria et al 2015).…”

Anisotropy and nonlinearity in superlattices II

“…Efficient numerical methods used here have been successfully applied to both inter-subband (Pereira and Faragai 2014;Pereira 2007Pereira , 2008Pereira , 2011Pereira et al 2007;Pereira and Tomić 2011) and inter-band transitions (Grempel et al 1996;Pereira et al 1994;Pereira and Henneberger 1997;Chow et al 1992) in quantum wells and superlattices. For completeness, we repeat here the main equations of Pereira (2016) for a guide to the reader, by starting with the interband polarization that has been used to describe superlattices as an effective anisotropic 3D material (Pereira 1995),…”

“…Thus the model is better suited for absorption in superlattices far from the 2D limit. In the quasi-2D limit of quantum wells, the full numerical solution (Grempel et al 1996;Pereira et al 1994;Pereira and Henneberger 1997) should be used. Thus, increase in nonlinearity is clearly demonstrated, which may be very important for truly 3D anisotropic new materials, but the high gain in quantum wells cannot be described by the method presented here.…”

Anisotropy and nonlinearity in superlattices

“…Efficient numerical methods used here have been successfully applied to both inter-subband (Pereira and Faragai 2014;Pereira 2007;Pereira 2008;Pereira et al 2007;Pereira and Tomić 2011;Pereira 2011) and inter-band transitions (Grempel et al 1996;Pereira et al 1994;Pereira and Henneberger 1997;Chow et al 1992) in quantum wells and superlattices.…”