Operation and Catastrophic Optical Degradation of II-VI Laser Diodes at Output Powers larger than 1 W

Abstract

An output power of 1.55 W, the highest ever reported, at 20 C has been achieved for a ZnCdSSe/ ZnSSe/ZnMgSSe separate-confinement heterostructure laser diode under short-pulsed operation. A differential quantum efficiency of 28% and a maximum conversion efficiency of 1.5% were obtained. The output power was limited by catastrophic optical damage (COD) of the facets, as proved by atomic force microscopy (AFM).Introduction Till this day, ZnSe-based heterostructures are the only available material system for semiconductor lasers emitting in the green spectral range. For many important practical applications, such as laser TV and polymer optical fibre (POF) communication, a high output power is required. For high power operation under cw conditions, advanced mounting technologies, for instance p-side down mounting, are essential to minimise the thermal stress for the device. Furthermore, the heat production in II-VI laser diodes (LDs) is much higher than in III-V LDs, because of the large series resistance of the devices, which is caused by the typically low doping level of the p-cladding layer. Pulsed conditions can be used for characterisation under minimum thermal stress, protecting the device against the typical degradation mechanism, the formation of darkline defects.In this paper, we will demonstrate 1.55 W optical output power operation of II-VI lasers, the highest value ever reported for these devices. Additionally, new insights in degradation mechanisms will be presented.

Chemical trends of stability and band alignment of lattice-matched II-VI/III-V semiconductor interfaces

“…For example, lattice-matched ZnO/GaN alloys have been suggested as a good candidate of electrode for high efficiency solar hydrogen production through photoelectrochemical water splitting 3,8,9 ; lattice-matched ZnSe/GaAs and ZnTe/GaSb heterojunctions are proposed to be high quality blue-green emitters 10,11 . ZnTe/GaSb have also been proposed as good candidate for tandem solar cell absorbers materials because GaSb has a band gap of 0.8 eV and ZnTe has a band gap of 2.4 eV, therefore, their alloys and superlattices can cover a large range of solar spectrum without significant change in the lattice constant 7 .…”

Stable interface structures of heterovalent semiconductor superlattices: The case of (GaSb) (ZnTe)

“…GaP films have been grown on Si (100) substrates by metal-organic chemical vapour deposition (MOVCD) for possible photovoltaic applications [13][14][15]; and ZnSe/GaAs heterostructures was prepared as high quality green light emitters [16,17]. In addition, ZnTe/GaSb also has great potential for tandem solar cell absorbers because GaSb has a direct band gap of 0.8 eV and ZnTe has a direct band gap of 2.4 eV [18]; therefore, their alloys and superlattices are capable of covering a large range of the solar spectrum without significant change in the lattice constant.…”

ZnSe∕GaAs(001)heterostructures with defected interfaces: Structural, thermodynamic, and electronic properties

“…We study the relative stability of the interfaces using Eq. (1). Although the precise values of the chemical potentials are unknown, strongly depending on the growth process and on the local environment, their range of variation and mutual relationships can be established in condition of thermodynamic equilibrium.…”