V. P. Evtikhiev

Subject of study. Distributed-feedback ring-cavity surface-emitting quantum-cascade lasers are studied. Aim of study. The aim is to realize stable single-mode emission in ring-cavity surface-emitting quantum-cascade lasers through a Bragg grating formed by direct-write ion beam lithography. Method. The selection of longitudinal whispering gallery modes owing to the fabrication of a second-order Bragg grating in the top waveguide cladding layers based on InP was implemented using direct-write ion beam lithography. Main results. The possibility of implementing stable single-mode emission in distributed-feedback ring-cavity surface-emitting quantum-cascade lasers with a Bragg grating formed by direct-write ion beam lithography was demonstrated. An increase in the etching depth of the grooves of the Bragg grating to 2.8 µm facilitated the implementation of stable single-mode emission at a temperature of 83 K. Single-mode emission was observed at a wavelength of 7.45 µm with a threshold current density of approximately 2kA/cm². The maximum side mode suppression ratio was 25 dB. Practical significance. Single-mode distributed-feedback ring-cavity surface-emitting quantum-cascade lasers are promising for the creation of compact gas sensors, wherein a laser and a photodetector of the mid-infrared spectral range are monolithically integrated on one chip.

We studied the influence of the focused ion beam milling of ridge waveguides on lasing parameters of edge-emitting lasers, based on a separate confinement double heterostructure. It is shown that there are three degrees of influence, according to the etching depth: modification of the waveguide properties only, a decrease in efficiency without changing the threshold current, and a simultaneous deterioration in the threshold current and efficiency with significant modification of the optical characteristics of the laser. Keywords: focused ion beam, semiconductor laser, optical waveguide, single mode lasing.

A new approach for calculating the ion dose spatial distribution of the focused ion beam is proposed. The approach is based on the analysis of the secondary electron microscopy image of the area irradiated by the focused ion beam.

We have created a quantum-cascade laser with 7–8 μm wavelength and surface radiation output through a lattice formed by focused ion beam etching of the upper cladding of the waveguide. The active area of the quantum-cascade laser heterostructure was formed on the basis of the solid alloy heteropair In_0.53Ga_0.47As/Al_0.48In_0.52As with two-phonon depletion of the cascade lower level. We demonstrate laser generation in the spectral band 7–8 μm for the created lasers with the selective ring resonator. The studies of the generation spectra for the temperatures in 8–77 K range have shown, that the mode spacing in the generation spectra of these lasers correspond to the whispering-gallery modes.

Light-emitting devices of modern photonics are based on the semiconductor structures containing layers with various physical parameters. To preserve initial parameters during focused ion beam (FIB) lithography, it is necessary to take into account the processes of radiation defect formation. Radiation-induced defects in target play role of nonradiative recombination centers leading to photoluminescence (PL) quenching. In our work, the FIB impact on the photoluminescence were examined using PL spectroscopy of milled Al_0.18Ga_0.82As/GaAs double heterostructure. In order to exclude photoexcited carriers losses in emitter layer, an experiment with subbarrier photoexcitation was organized. Finally, we compare our experimental findings with theoretical data proposed by stopping and range of ions in matter (SRIM) calculation.

A technique for direct study of the distribution of the applied voltage within a quantum cascade laser (QCL) has been developed. The detailed profile of the potential in the laser claddings and laser core region has been obtained by gradient scanning Kelvin probe force microscopy (KPFM) across the cleaved facets for two mid-infrared quantum cascade laser structures. An InGaAs/InAlAs quantum cascade device with InP claddings demonstrates a linear potential distribution across the laser core region with constant voltage drop across the doped claddings. By contrast, a GaAs/AlGaAs device with AlInP claddings has very uneven potential distribution with more than half of the voltage falling across the claddings and interfaces around the laser core, greatly increasing the overall voltage value necessary to achieve the lasing threshold. Thus, KPFM can be used to highlight design and fabrication flaws of QCLs.

The effect of annealing temperature and time on the luminescence intensity of the InGaN/GaN heterostructure subjected to ion beam etching was studied. We show that annealing at a temperature...

The work presents experimental data of Ga+ focused ion beam etching of disc and ring patterns in Si3N4/GaN structure. The reasons for the difference in etching depth between the discs and...

The effect of the growth temperature and the flow of trimethylgallium on the process of selective epitaxy of gallium nitride in windows of submicron size have been studied. The conditions...

The ion-beam etching of AlGaAs/GaAs heterostructures gives rise to radiation defects and, as a result, leads to photoluminescence quenching. Annealing at 620°C in an atmosphere of As almost...