First step to Si photonics: synthesis of quantum dot light-emitters on GaP substrate by MBE (original) (raw)
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Coherent integration of photonics on silicon through the growth of nanostructures on GaP/Si
Quantum Sensing and Nanophotonic Devices Ix, 2012
Selected results obtained in the framework of MBE grown nanostructure for photonics on silicon are repsented in this paper. We present first a comprehensive study of GaAsPN/GaPN quantum wells (QWs) grown onto GaP substrates, in the light of a comparison with their N-free GaAsP/GaP QWs counterpart system. High density of small InGaAs/GaP Quantum Dots are presented next with their PL properties. Finally, RT photoluminescence properties of GaAsPN/GaPN QWs onto Si substrate are presented and discussed in term of carrier injection efficiency. However, for future development, optical properties of the active area must be improved and are tightly bound to the structural perfection of the GaP/Si template layer. To address this point, structural analyses including X-Ray Diffraction (lab setup and synchrotron) and Transmission Electron Microscopy have been performed, with a particular care for typical III-V/Si defect characterisation. First results of Si buffer layer growth are also presented as a perspective for future low defect MBE grown GaP/Si template layers.
Journal of Crystal Growth, 2008
A two-step growth process of gallium phosphide (GaP) epilayer on silicon substrate is carried out using metal organic vapor-phase epitaxy (MOVPE). This process includes the growth of a low-temperature GaP nucleating layer and a high-temperature GaP epilayer. In the first step, a GaP nucleating layer of thickness 80nmwithhighV/IIIratio80 nm with high V/III ratio 80nmwithhighV/IIIratio1725 is grown at 425 1C. This is followed by the growth of a GaP layer of thickness 760nmwithV/IIIratio760 nm with V/III ratio 760nmwithV/IIIratio100 at 770 1C. The total thickness of the epilayer is 845nmasmeasuredonacross−sectionbyascanningelectronmicroscope(SEM).AGaPlayergrownbythetwostepgrowthprocessshowssignificantimprovementinmorphologycomparedwiththatgrownbythesingle−stepprocess,asconfirmedbyRamanandSEMstudies.High−resolutionX−raydiffractionstudiesshowthattheepilayerisofsinglecrystallinenatureandstructurallycoherentwiththesiliconsubstrate.Epilayersgrownusingthetwo−stepprocessshowreduceddislocationdensityandmicro−strains,withsignificantimprovementsintheirstructuralproperties.Theselayersalsoshown−typebehaviorwithanelectrondensityof845 nm as measured on a cross-section by a scanning electron microscope (SEM). A GaP layer grown by the twostep growth process shows significant improvement in morphology compared with that grown by the single-step process, as confirmed by Raman and SEM studies. High-resolution X-ray diffraction studies show that the epilayer is of single crystalline nature and structurally coherent with the silicon substrate. Epilayers grown using the two-step process show reduced dislocation density and micro-strains, with significant improvements in their structural properties. These layers also show n-type behavior with an electron density of 845nmasmeasuredonacross−sectionbyascanningelectronmicroscope(SEM).AGaPlayergrownbythetwostepgrowthprocessshowssignificantimprovementinmorphologycomparedwiththatgrownbythesingle−stepprocess,asconfirmedbyRamanandSEMstudies.High−resolutionX−raydiffractionstudiesshowthattheepilayerisofsinglecrystallinenatureandstructurallycoherentwiththesiliconsubstrate.Epilayersgrownusingthetwo−stepprocessshowreduceddislocationdensityandmicro−strains,withsignificantimprovementsintheirstructuralproperties.Theselayersalsoshown−typebehaviorwithanelectrondensityof8.5 Â 10 17 cm À3 , while the single-step-grown layers show p-type behavior. This change in type is explained by a reduced/increased incorporation of silicon into phosphorus/gallium sites, respectively, i.e. a predominant donor nature of silicon in GaP grown by the two-step growth process. Photoluminescence (PL), surface photovoltage spectroscopy (SPS) and transport measurements confirm a significant reduction in sub-band gap states and carrier density.
Journal of Crystal Growth, 2011
We report the growth of self-assembled InAs/GaAs quantum dots (QDs) on Si, Ge/Si and germanium-oninsulator-on-silicon (GeOI) substrates by metal organic chemical vapor deposition. GaAs layers with lower surface roughness (root mean square roughness of 1 nm) and higher structural quality were obtained on Ge/Si and GeOI compared to those obtained on Si substrate. We showed that the introduction of a QD layer within the GaAs buffer layer was efficient in suppressing the propagation of anti-phase domains to the GaAs surface for both cases of Ge/Si and GeOI substrates. Coalescence-free QDs with densities above 10 10 cm À 2 and ground state emission in the 1.3 mm band at room temperature were obtained on all substrates. QDs grown on GeOI yield the highest photoluminescence (PL) intensity, and quite remarkably, have similar PL intensity as those grown on GaAs substrate. These results suggest the better suitability of GeOI substrate compared to Si or Ge/Si substrates for the monolithic integration of QD-based lasers on silicon (or any other III-V photonic device) for silicon photonics.
O-Band Emitting InAs Quantum Dots Grown by MOCVD on a 300 mm Ge-Buffered Si (001) Substrate
Nanomaterials, 2020
The epitaxy of III-V semiconductors on silicon substrates remains challenging because of lattice parameter and material polarity differences. In this work, we report on the Metal Organic Chemical Vapor Deposition (MOCVD) and characterization of InAs/GaAs Quantum Dots (QDs) epitaxially grown on quasi-nominal 300 mm Ge/Si(001) and GaAs(001) substrates. QD properties were studied by Atomic Force Microscopy (AFM) and Photoluminescence (PL) spectroscopy. A wafer level µPL mapping of the entire 300 mm Ge/Si substrate shows the homogeneity of the three-stacked InAs QDs emitting at 1.30 ± 0.04 µm at room temperature. The correlation between PL spectroscopy and numerical modeling revealed, in accordance with transmission electron microscopy images, that buried QDs had a truncated pyramidal shape with base sides and heights around 29 and 4 nm, respectively. InAs QDs on Ge/Si substrate had the same shape as QDs on GaAs substrates, with a slightly increased size and reduced luminescence intensi...
Long-Wavelength InAs/GaAs Quantum-Dot Light Emitting Sources Monolithically Grown on Si Substrate
Photonics, 2015
Direct integration of III-V light emitting sources on Si substrates has attracted significant interest for addressing the growing limitations for Si-based electronics and allowing the realization of complex optoelectronics circuits. However, the high density of threading dislocations introduced by large lattice mismatch and incompatible thermal expansion coefficient between III-V materials and Si substrates have fundamentally limited monolithic epitaxy of III-V devices on Si substrates. Here, by using the InAlAs/GaAs strained layer superlattices (SLSs) as dislocation filter layers (DFLs) to reduce the density of threading dislocations. We firstly demonstrate a Si-based 1.3 µm InAs/GaAs quantum dot (QD) laser that lases up to 111 °C, with a low threshold current density of 200 A/cm 2 and high output power over 100 mW at room temperature. We then demonstrate the operation of InAs/GaAs QD superluminescent light emitting diodes (SLDs) monolithically grown on Si substrates. The fabricated two-section SLD exhibits a 3 dB linewidth of 114 nm, centered at ～1255 nm with a corresponding output power of 2.6 mW at room temperature. Our work complements hybrid integration using wafer bonding and represents a significant milestone for direct monolithic integration of III-V light emitters on Si substrates.