The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We have investigated the growth, structural properties and photoluminescence of novel GaAs/AlGaAs radial heterostructure nanowires, fabricated by metalorganic chemical vapour deposition. The effect of growth temperature on nanowire morphology is discussed. Strong photoluminescence is observed from GaAs nanowires with AlGaAs shells. Core/multishell nanowires, of GaAs cores clad in several alternating...
In the coming years, long electrical interconnect circuits may be substituted by optical ones in computer integrated circuits. Photonic crystal devices have the potential of being included in future optical interconnect systems. In this presentation, we analyse a few photonic crystal devices which target this application
InGaAs quantum dots (QDs) and nanowires have been grown on GaAs by metal-organic chemical vapour deposition on GaAs (100) and (111)B substrates, respectively. InGaAs QD lasers were fabricated and characterised. Results show ground-state lasing at about 1150 nm in devices with lengths greater than 2.5 mm. We also observed a strong influence of nanowire density on nanowire height specific to nanowires...
The spectral width of terahertz emission from ion-implanted terahertz emitters increases with ion damage, owing to ultrafast carrier capture. Carrier dynamics simulations reinforce these findings. Optical-pump, terahertz-probe experiments confirm the sub-picosecond lifetimes of these materials.
We present a terahertz radiation detector that measures both transverse components of a terahertz single cyclepsilas electric field, allowing the study of polarization dependent properties of materials. Measurements of birefringence in quartz are presented.
The amount of information that can be handled by computers is increasing every year. In order to satisfy this growing demand, computers need to augment the number of components in a chip and, at the same time, operate at higher speeds. This is leading long electrical interconnects to reach their limits in terms of speed and power dissipation, motivating the search of new alternatives. One of the alternatives...
The growth mechanism and properties of GaAs/InAs nanowires prepared by metalorganic chemical vapor deposition are investigated. Vertical InAs nanowires on GaAs (111)B substrates are successfully grown despite the large lattice mismatch (-7.2%). The crystallographic perfection of InAs nanowires is confirmed by hexagonal or triangular cross section. An interesting L-shaping of GaAs/InAs heterostructure...
A major problem facing quantum dot lasers is gain saturation. This is caused by low gain volume and also a low wavefunction overlap within the quantum dots. One method to increase the gain volume is to increase the number of layers of quantum dots. This paper compares the characteristics of lasers with three and five layers of quantum dots. It is shown that five layer devices can be made with improved...
We have investigated the quantum well interdiffusion of Inx Ga1-xAs/InP QWs with different In composition using proton irradiation. 50 KeV proton implantation with various doses from 5times1014 H/cm2 with subsequent annealing at 750deg for 60 sec were used to induce the atomic intermixing process. Photoluminescence was performed to measure the bandgap energy shift between the unimplanted and implanted...
The role of increasing GaAs thickness (0-3 nm) to improve the optical quality and tune the emission wavelength of InAs quantum dots (QDs) grown on GaInAsP buffer on (100) InP substrate by metalorganic chemical vapor deposition was studied. The growth of a very thin (0.3 nm-0.6 nm) GaAs interlayer between GaInAsP buffer and InAs QDs layer reduced the mean height and size fluctuation of InAs QDs by...
We demonstrate that selective-area-epitaxy can be used to selectively tune the properties of InGaAs quantum-dots in different regions of the same wafer. We report single step, MOCVD growth of different sized dots, luminescing at wavelengths spread over a range of 100 nm
InAs/GaAs quantum dots (QDs) were grown by low pressure metal-organic chemical vapour deposition in the Stranski-Krastanow growth mode. We describe the influence of growth parameters such as coverage, the V/III ratio, growth temperature and growth interrupts on the QD nucleation and the importance of avoiding formation of larger islands which are particularly susceptible to dislocations. After an...
The novel hot electron injection laser (HEL), a three-terminal vertically integrated transistor-laser structure, is designed to investigate and possibly utilize the effects of carrier-heating on the optical gain and wavelength chirp. Simulations show the potential of carrier heating assisted gain switching to directly modulate the optical field intensity at frequencies up to 100 GHz while maintaining...
An InGaAsN quantum dot (QD) laser structure and a reference InGaAs single quantum well (QW) laser structure were grown on GaAs substrates by metalorganic chemical vapor deposition. A comparison study of photocurrent spectra of these two structures was performed. It was found that InGaAsN QD devices exhibit a lower-energy transition and shows a smaller quantum-confined Stark effect than InGaAs QW devices...
Enhancement of interdiffusion in GaAs/AlGaAs quantum wells (QWs) due to anodic oxides was studied. Photoluminescence and diffused QW modeling were used to understand the effects of intermixing on the QW structure. The activation energy is similar to those obtained from SiO/sub 2/ cap annealed quantum well structures.
Summary form only given. We have demonstrated the growth of good quality, high reflectivity mirrors at wavelengths as low as 550 nm and electroabsorption between 580 and 540 nm in AlGaAs/AlAs MQWs. We present details on these and results on the characterization of the modulator grown by integrating the mirror and the MQW structures in a Fabry-Perot cavity.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.