Growth and properties of the self‐catalyzed heterostructured GaP nanowires (NWs) with GaP1 − xAsx insertions in the form of nanodiscs (NDs) grown by means of molecular‐beam epitaxy on Si (111) substrate are studied. To obtain the NDs with the different composition and optoelectronic properties, the ratio of As and P fluxes is varied. Structural properties of the synthesized heterostructures are characterized by means of transmission electron microscopy. Energy dispersive X‐ray spectroscopy is used to study chemical composition of the NDs. The maximum achieved fraction x in the NDs is nearly 60%. Sublinear dependence of As concentration in the ND on the As/P flux ratio is observed and theoretical description for the observed phenomenon is provided. The proposed model can be used to estimate the predicted As/P ratio for the synthesis of GaPAs NDs as well as NWs of the required composition. Microphotoluminescence (μPL) studies demonstrate the appearance of broadband PL signal in the spectral range between 600 and 700 nm, corresponding to the NDs with different compositions. Spectra intensity modulation is found due to longitudinal Fabry–Pérot‐type resonances in the individual NWs.

High-performance injection microdisk lasers grown on Si substrate are demonstrated for the first time. Continuous wave lasing in microlasers with diameters from 14 to 30 µm is achieved at room temperature. The minimal threshold current density of 600 A/cm 2 (room temperature, continuous wave regime, heatsink-free uncooled operation) is comparable to that of high-quality microdisk lasers on GaAs substrates. Microlasers on silicon emit in the wavelength range of 1320-1350 nm via the ground state transition of InAs/InGaAs/GaAs quantum dots. High stability of the lasing wavelength (dλ/dI=0.1 nm/mA) and low specific thermal resistance of 4×10 -3 о С×cm 2 /W are demonstrated. © 2017 Optical Society of AmericaOCIS codes : (140.5960 Semiconductor lasers; (140.3945 Microcavities).http://dx.doi.org/10.1364/OL.99.099999Realization of compact silicon-based lasers capable for reliable operation at elevated temperatures is a subject of persistent attempts of many research groups worldwide. To date, several approaches have been proposed to realize light source on silicon. This includes the hybrid III-V-silicon integration, that can be done using different bonding techniques such as flip-chip bonding [1] or molecular bonding [2,3]. For this purpose, InP-based laser structures with InAsP/InGaAsP quantum wells (QWs) were used. The highest operation temperature for InP-based microring lasers with a diameter of 50 μm is 65 o C[4]. For further increase of the operating temperature (up to 105C) a special thermal shunt design improving thermal conductivity is required [5]. The highest operating temperature of InP-based microlasers is limited by small energy of the carrier confinement in the active region (small conduction band offsets). Moreover, it is often in bonded structures that the major part of the optical field is located in the silicon waveguide and its overlap with the III-V active region is only a few percents. Another group of integration methods is based on direct epitaxial growth of III-V active layers on silicon substrates. An approach based on Ge/Si (001) virtual substrate [6] has been recently used to achieve room-temperature lasing in InGaAs/GaAs quantum well microdisk (MD) lasers with 23 µm diameter [7]. The minimal threshold current density was 28 kA/cm 2 reflecting a high sensitivity of a quantum well active region to various defects originated from both epitaxial growth on silicon and damaged microresonator sidewalls. In this respect quantum dots (QDs) can offer advantageous characteristics owing to a suppressed lateral transport of charge carriers which prevents their diffusion towards non-radiate recombination centers. Owing to this unique property of QDs, a significant progress has been demonstrated in the past years in realization of III-V-Si injection lasers [8][9][10]. A low density of threading dislocations on the order of 10 5 cm −2 in the III-V epilayers grown on silicon (100)-oriented substrates with 4 o offcut is achieved by combining a nucleation layer and dislocation filter layers with in situ ther...

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We review epitaxial formation, basic properties, and device applications of a novel type of nanostructures of mixed (0D/2D) dimensionality that we refer to as quantum well-dots (QWDs). QWDs are formed by metalorganic vapor phase epitaxial deposition of 4–16 monolayers of InxGa1−xAs of moderate indium composition (0.3 < x < 0.5) on GaAs substrates and represent dense arrays of carrier localizing indium-rich regions inside In-depleted residual quantum wells. QWDs are intermediate in properties between 2D quantum wells and 0D quantum dots and show some advantages of both of those. In particular, they offer high optical gain/absorption coefficients as well as reduced carrier diffusion in the plane of the active region. Edge-emitting QWD lasers demonstrate low internal loss of 0.7 cm−1 and high internal quantum efficiency of 87%. as well as a reasonably high level of continuous wave (CW) power at room temperature. Due to the high optical gain and suppressed non-radiative recombination at processed sidewalls, QWDs are especially advantageous for microlasers. Thirty-one μm in diameter microdisk lasers show a high record for this type of devices output power of 18 mW. The CW lasing is observed up to 110 °C. A maximum 3-dB modulation bandwidth of 6.7 GHz is measured in the 23 μm in diameter microdisks operating uncooled without a heatsink. The open eye diagram is observed up to 12.5 Gbit/s, and error-free 10 Gbit/s data transmission at 30 °C without using an external optical amplifier, and temperature stabilization is demonstrated.

Microdisk lasers demonstrate high performance and low threshold characteristics due to supporting of whispering gallery modes with a high quality factor. One of the challenging problems impeding some practical applications of whispering gallery mode lasers is that they have isotropic emission predominantly lying in the plane of the cavity. In this work, we present a novel method that provides both enhancement of the laser emission and modifies its directivity, making the vertical direction favorable. Electromagnetic energy outcouples from the cavity through the platinum−carbon plasmonic wire nanoantenna grown by electron-beam assisted deposition right up the side wall of the cavity. Evanescent field of whispering gallery mode excites surface plasmon polariton which propagates along the nanoantenna and scatters at its tip. We demonstrate 20× enhancement of the dominant mode intensity with 24 dB of side mode suppression increment without essential worsening of the Q-factor which remains over 3 × 10 4 . The proposed approach of the efficient control over the spectrum, directivity, and emission efficiency from microdisk lasers could be very promising for many practical applications from telecommunication technologies to biosensing.