Blue‐Green ZnSe Laser Diodes for Optoelectronics. Present State at Würzburg University

Abstract

A review is given on the research activities at Wiirzburg University in the field of blue-green emitting ZnSe laser diodes. Of great importance for both the structural and electrical properties is the possibility to grow a GaAs buffer layer on the GaAs substrate prior to the 11-VI growth. Pulsed room temperature lasing with a duty cycle up to 17% is obtained using quaternary ZnMgSSe cladding layers, ternary ZnSSe waveguides, and a single CdZnSe quantum well. Important issues for long-term stability of such laser diodes like growth start, p-type doping, and ohmic contacts are discussed.

Diffusion of Au in ZnSe and its dependence on crystal quality

“…The use of an epitaxial buffer layer has been shown to reduce the formation of these defects. 18 The difference in the gold diffusivity in sample series II and III can possibly be explained by the difference in the Se to Zn beam pressure ratios during growth, 2.0 and 2.5 for sample series II and III, respectively. This difference can result in higher defect concentration in sample series II and thus higher diffusivity.…”

Propagation of femtosecond pulses in thin ZnSe layers

“…They were grown by molecular-beam epitaxy (MBE) in a two-chamber Riber 2300 system at Wiirzburg University. To ensure strain in the ZnSe layers to be homogeneous, the barriers are intended to be lattice matched to the GaAs substrate (z = 0.06), and the nominal thickness of the ZnSe layer (23, 50, and 100 nm; in the following, these intended thicknesses will be used to refer to the different samples) is kept well below the critical one (~5.200 nm [18]). For transmission experiments the opaque GaAs substrate was removed by grinding and subsequent chemical etching.…”

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

“…The investigated structures were grown in a multi-chamber RIBER 2300 MBE system with a 11-VI and 111-V chamber interconnected by a UHV transfer module. Important for the high structural quality is the deposition of a GaAs buffer layer in the 111-V chamber on the (100) GaAs substrate prior to the 11-VI growth (for details, see [30]).…”