Preliminary results of determination of chemical element concentrations in the aerosol of Venus clouds

An X-ray radiometeric experiment is described along with the results of measurements of the elemental composition of aerosols in Venusian clouds. A preliminary analysis of the data showed that sulfur is present in the range of heights 63 to 47 km with mean content of 5.8 mg/cu m and that chlorine is present in the height range 61 t0 52 km with a mean content of 4.1 mg/cu m. The results of measurements in the range 52 to 47 km may come to an agreement if phosphorus is present in the aerosol with a mean concentration of 7.7 mg/cu m

Monolithic and hybrid integration of InAs/GaAs quantum dot microdisk lasers on silicon

A method of hybrid integration of quantum dot microdisk lasers with silicon wafer is proposed and realized. In addition to the possibility of combining microlasers with various silicon-based electronic and photonic devices, this makes it possible to significantly improve heat removal from the active region of the microlaser. The thermal resistance normalized to the mesa area reaches the level of about 0.002 (K/W)*cm2, which is significantly lower than the corresponding values of QD microlasers on GaAs substrate and monolithically grown on Si. As a result, the threshold current as well as current-induced shift of emission wavelength are reduced in continuous-wave regime

Increasing the quantum efficiency of InAs/GaAs QD arrays for solar cells grown by MOVPE without using strain-balance technology

Research into the formation of InAs quantum dots (QDs) in GaAs using the metalorganic vapor phase epitaxy technique ispresented. This technique is deemed to be cheaper than the more often used and studied molecular beam epitaxy. The bestconditions for obtaining a high photoluminescence response, indicating a good material quality, have been found among awide range of possibilities. Solar cells with an excellent quantum ef?ciency have been obtained, with a sub-bandgapphoto-response of 0.07 mA/cm2per QD layer, the highest achieved so far with the InAs/GaAs system, proving the potentialof this technology to be able to increase the ef?ciency of lattice-matched multi-junction solar cells and contributing to abetter understanding of QD technology toward the achievement of practical intermediate-band solar cells

Near field scanning optical microscopy for investigation of high power semiconductor lasers

В данной работе были исследованы карты распределения ближнего поля InGaAs/GaAs/AlGaAs полосковых инжекционных лазеров при различных токах накачки. Было показано, что в структурах, состоящих из двух резонансно связанных волноводов, наблюдается подавление мод высоких порядков.Near field intensity distributions of InGaAs/GaAs/AlGaAs lasers including broadened waveguides based on coupled large optical cavity (CLOC) structures were investigated. It was demonstrated that scanning near field optical microscopy gives direct proof of suppressing the transverse high-order mode lasing.Работа выполнена при поддержке РНФ (соглашение № 14-42-00006-П

Optical method of estimation of degree of atomic ordering within quaternary semiconductor alloys Related Articles Optical method of estimation of degree of atomic ordering within quaternary semiconductor alloys

Effect of light Si-doping on the near-band-edge emissions in high quality GaN J. Appl. Phys. 112, 053104 (2012) Nucleation features and energy levels of type-II InAsSbP quantum dots grown on InAs(100) substrate Appl. Phys. Lett. 101, 093103 (2012) Optomechanical photoabsorption spectroscopy of exciton states in GaAs Appl. Phys. Lett. 101, 082107 (2012) Light emission lifetimes in p-type δ-doped GaAs/AlAs multiple quantum wells near the Mott transition J. Appl. Phys. 112, 043105 (2012) Impact of substrate-induced strain and surface effects on the optical properties of InP nanowires Appl. Phys. Lett. 101, 072101 (2012) Additional information on J. Appl. Phys. It is well known that within metal-organic vapor-phase epitaxy grown semiconductor ternary alloys atomically ordered regions are spontaneously formed during the epitaxial growth. This ordering leads to bandgap reduction and to valence bands splitting, and therefore to anisotropy of the photoluminescence emission polarization. The same phenomenon occurs within quaternary semiconductor alloys. While the ordering in ternary alloys is widely studied, for quaternaries there have been only a few detailed experimental studies of it, probably because of the absence of appropriate methods of its detection. Here, we propose an optical method to reveal atomic ordering within quaternary alloys by measuring the photoluminescence (PL) emission polarization. The measured and calculated angular dependencies of the polarized PL emission intensity from (100) surface for two semiconductor alloys: Ga 0.51 In 0.49 P and (Al 0.3 Ga 0.7 ) 0.5 In 0.5 P are compared in order to estimate the degree of atomic ordering within these alloys. The method shows that the quaternary (Al 0.3 Ga 0.7 ) 0.5 In 0.5 P alloy is a highly ordered structure with the value of the atomic ordering degree close to 0.5. V C 2012 American Institute of Physics. [http://d