High Quality InP Research Articles

4,4'-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) Lead Iodide C30H22N2Pb2I6: A Highly Luminescent, Chemically and Thermally Stable One-Dimensional Hybrid Iodoplumbate.

A new one-dimensional hybrid iodoplumbate, namely, 4,4'-(anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) lead iodide C30H22N2Pb2I6 (AEPyPbI), is reported here for the first time with its complete characterization. The material exhibits remarkable thermal stability (up to 300 °C), and it is unreactive under ambient conditions toward water and atmospheric oxygen, due to the quaternary nature of the nitrogen atoms present in the organic cation. The cation exhibits strong visible fluorescence under ultraviolet (UV) irradiation, and when its iodide is combined with PbI2, it forms AEPyPb2I6, an efficient light-emitting material, with a photoluminescence emission intensity comparable to that of high-quality InP epilayers. The structure determination was obtained using three-dimensional electron diffraction, and the material was extensively studied by using a wide range of techniques, such as X-ray powder diffraction, diffuse reflectance UV-visible spectroscopy, thermogravimetry-differential thermal analysis, elemental analysis, Raman and infrared spectroscopies, and photoluminescence spectroscopy. The emissive properties of the material were correlated with its electronic structure by using state-of-the-art theoretical calculations. The complex, highly conjugated electronic structure of the cation interacts strongly with that of the Pb-I network, giving rise to the peculiar optoelectronic properties of AEPyPb2I6. The material, considering its relatively easy synthesis and stability, shows promise for light-emitting and photovoltaic devices. The use of highly conjugated quaternary ammonium cations may be useful for the development of new hybrid iodoplumbates and perovskites with optoelectronic properties tailored for specific applications.

Design and optimization of complex single heater for vertical gradient freeze (VGF) grower

A complex single heater is designed for a VGF process to decrease process complexity caused by the use of a multi-heater system. To do this, a set of design criteria is selected to ensure that the final quality of the crystal is acceptable. Then a 3D transient finite element model is coupled with a new optimization procedure. All important physical phenome a such as temperature distribution, turbulent melt flow, thermal stress and crystal front shape are monitored and controlled during crystal growth. Using these, a single heater is designed for 4″ InP VGF crystal growth which meets all design criteria. It is concluded that using the complex single heater, high quality InP crystal growth by VGF process is possible.

Synthesis, Structure, and Characterization of 4,4'-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) Bismuth Iodide (C30H22N2)3Bi4I18, an Air, Water, and Thermally Stable 0D Hybrid Perovskite with High Photoluminescence Efficiency.

4,4'-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) bismuth iodide (C30H22N2)3Bi4I18 (AEPyBiI) was obtained as a black powder by a very simple route by mixing an acetone solution of BiI3 and an aqueous solution of C30H22N2I2. This novel perovskite is air and water stable and displays a remarkable thermal stability up to nearly 300 °C. The highly conjugated cation C30H22N2 2+ is hydrolytically stable, being nitrogen atoms quaternarized, and this accounts for the insensitivity of the perovskite toward water and atmospheric oxygen under ambient conditions. The cation in aqueous solution is highly fluorescent under UV irradiation (emitting yellow-orange light). AEPyBiI as well is intensely luminescent, its photoluminescence emission being more than 1 order of magnitude greater than that of high-quality InP epilayers. The crystal structure of AEPyBiI was determined using synchrotron radiation single-crystal X-ray diffraction. AEPyBiI was extensively characterized using a wide range of techniques, such as X-ray powder diffraction, diffuse reflectance UV-vis spectroscopy, Fourier transform infrared (FTIR) and Raman spectroscopies, thermogravimetry-differential thermal analysis (TG-DTA), elemental analysis, electrospray ionization mass spectroscopy (ESI-MS), and photoluminescence spectroscopy. AEPyBiI displays a zero-dimensional (0D) perovskite structure in which the inorganic part is constituted by binuclear units consisting of two face-sharing BiI6 octahedra (Bi2I9 3- units). The C30H22N2 2+ cations are stacked along the a-axis direction in a complex motif. Considering its noteworthy light-emitting properties coupled with an easy synthesis and environmental stability, and its composition that does not contain toxic lead or easily oxidable Sn(II), AEPyBiI is a promising candidate for environmentally friendly light-emitting devices.

III–V Microwires with Reversed Ridge Waveguides Selectively Grown on Pre-Patterned Si Substrates

To construct functional photonic integrated circuits, an efficient and compact laser is expected to be incorporated into the complementary metal–oxide–semiconductor platform. Monolithic integration of III–V lasers on pre-patterned Si substrates by the aspect ratio trapping method is a promising solution. Here, microwires with reversed ridge waveguides (RRWs) on pre-patterned Si substrates were reported. By metal–organic chemical vapor deposition, high-quality InP microwires with RRWs were obtained, and InGaAs/InGaAsP multi-quantum-well structures with InGaAsP separate confinement hetero structure (SCH–MQW) were successfully achieved. The SCH–MQW structure was buried in the InP microwire, which was beneficial for transferring the heat generated in the active region. The micron size also contributes to the efficiency of thermal diffusion. Further, simulation results showed that the metal absorption loss could be less than 4 dB/cm by properly controlling the contact area between metal electrodes and microwires. This proposed structure opens up an alternative pathway for electrically driven III–V lasers seamlessly interfaced with Si-photonics.

Direct Epitaxial Growth of InP Nanowires on MoS2 with Strong Nonlinear Optical Response

Mixed-dimensional van der Waals heterostructures are promising for research and technological advances in photonics and optoelectronics. Here we report vapor–liquid–solid (VLS) method-based van der Waals epitaxy of one-dimensional InP nanowires (NWs) directly on two-dimensional MoS2. With optimized growth parameters (V/III ratio, flow rates of precursors, and growth temperature), we successfully grow high-quality InP NWs on MoS2. The density and vertical yield of NWs on MoS2 are significantly high. Due to the unique properties of both materials, we observe strong linear and nonlinear optical responses from the NW/MoS2 heterostructures. Intriguingly, in addition to strong second and third harmonic responses, the mixed-dimensional heterostructures show odd-order high harmonic generation up to seventh order. Our findings can open new possibilities for advancing attosecond physics on a new platform of mixed-dimensional heterostructures.

Aminophosphate precursors for the synthesis of near-unity emitting InP quantum dots and their application in liver cancer diagnosis.

InP quantum dots (QDs) are a promising and environment-friendly alternative to Cd-based QDs for in vitro diagnostics and bioimaging applications. However, their poor fluorescence and stability severely limit their biological applications. Herein, we synthesize bright (∼100%) and stable InP-based core/shell QDs by using cost-effective and low-toxic phosphorus source, and then aqueous InP QDs are prepared with quantum yield over 80% by shell engineering. The immunoassay of alpha-fetoprotein can be detected in the widest analytical range of 1-1000 ng ml-1 and the limit of detection of 0.58ngml-1 by using those InP QDs-based fluorescent probes, making it the best-performing heavy metal-free detection reported so far, comparable to state-of-the-art Cd-QDs-based probes. Furthermore, the high-quality aqueous InP QDs exhibit excellent performance in specific labeling of liver cancer cells and in vivo tumor-targeted imaging of live mice. Overall, the present work demonstrates the great potential of novel high-quality Cd-free InP QDs in cancer diagnosis and image-guided surgery.

A mitochondrial-targetable fluorescent probe based on high-quality InP quantum dots for the imaging of living cells

Numerous cellular functions are closely reliant on mitochondria and so the capability to conduct long-term stable studies of their activity is of great importance. However, current commercial mitochondrial probes are severely limited in their ability to trace mitochondria due to their inherently poor stability. Here, for the first time, we designed a novel mitochondrial fluorescent probe using InP quantum dots (QDs) as a fluorescent master and skillfully combined with (3-carboxypropyl)triphenylphosphine (TPP) for specific recognition. The bespoke InP QDs probes described here exhibited clear advantages, including simple and low-cost synthesis, high quantum yields, extremely low toxicity, good biocompatibility, and excellent photochemical stability, thus representing a versatile, novel mitochondrial fluorescent probe, particularly suitable in applications traditionally undertaken by Cd-based QDs in biological fields.

Aminophosphine-derived, high-quality red-emissive InP quantum dots by the use of an unconventional in halide

Bright-, sharp-emissive red InP quantum dots were synthesized with the combination of In bromide and aminophosphine and further employed as efficient electroluminescent emitters.

A Mitochondrial-Targetable Fluorescent Probe Based on High-Quality Inp Quantum Dots for the Imaging of Living Cells

A Mitochondrial-Targetable Fluorescent Probe Based on High-Quality Inp Quantum Dots for the Imaging of Living Cells

High electron mobility InP grown by solid source molecular beam epitaxy

High-quality InP is grown by solid source molecular beam epitaxy using white phosphorus source in a three-zone valved cracker cell. The growth temperature, growth rate and substrate desorption process have been adjusted to optimize the structural, electrical and optical properties. The photon and carrier scattering dynamics are investigated by temperature-dependent photoluminescence and electron Hall mobility. The 5-μm-thick sample presents stronger photoluminescence, solo carrier recombination scheme and inferior impurity scattering comparing to the 1-μm-thick sample. The high electron mobility of 137000 cm2/V·s at 77 K has been achieved for the 5-μm-thick InP layer.

Influence of Growth Temperature of the Nucleation Layer on the Growth of InP on Si (001)

InP layers grown on Si (001) were achieved by the two-step growth method using gas source molecular beam epitaxy. The effects of growth temperature of nucleation layer on InP/Si epitaxial growth were investigated systematically. Cross-section morphology, surface morphology and crystal quality were characterized by scanning electron microscope images, atomic force microscopy images, high-resolution X-ray diffraction (XRD), rocking curves and reciprocal space maps. The InP/Si interface and surface became smoother and the XRD peak intensity was stronger with the nucleation layer grown at 350 °C. The Results show that the growth temperature of InP nucleation layer can significantly affect the growth process of InP film, and the optimal temperature of InP nucleation layer is required to realize a high-quality wafer-level InP layers on Si (001).

Synthesis of Colloidal Blue-Emitting InP/ZnS Core/Shell Quantum Dots with the Assistance of Copper Cations.

Colloidal InP quantum dots (QDs) have been considered as one of the most promising candidates for display and biolabeling applications because they are intrinsically toxicity-free and exhibit high photoluminescence. On account of the uncontrollable nucleation and growth during the synthesis of InP, obtaining high-quality blue-emitting InP QDs with uniform size distribution remains a challenge. Herein, we employ a novel synthetic approach for producing blue-emitting InP/ZnS core/shell QDs with the assistance of copper cations. The studies reveal that the copper ions could combine with phosphorus precursor to form hexagonal Cu3-xP nanocrystals, which competed with the nucleation process of InP QDs, resulting in the smaller sized InP QDs with blue photoluminescence emission. After the passivation of InP QDs with the ZnS shell, the synthesized InP/ZnS core/shell QDs present bright blue emission (∼425 nm) with a photoluminescence quantum yield of ∼25%, which is the shortest wavelength emission for InP QDs to date. This research provides a new way to synthesize ultrasmall semiconductor nanocrystals.

Improved quality of InP layer on GaAs substrates by using compositionally modulated step-graded AlGaInAs buffers

Improved quality of metal–organic chemical vapor deposition grown InP layer on GaAs substrate was achieved by using compositional modulated step-graded AlGaInxAs (x = 0.05–0.52) buffers. With the insertion of tensile stained AlGaInAs layers into the compressive buffers, we obtained a high crystal quality InP layer with a smooth surface and low threading dislocation confirmed by atomic force microscopy, transmission electron microscopy, photoluminescence and X-ray diffraction reciprocal space mapping. This indicated that the tensile strained AlGaInAs layers into the compressive AlGaInAs layers can change the glide direction and facilitate annihilation reactions of dislocations, and the interfaces also can prevent the vertical growth of threading dislocations propagating through the structures. The results show that the compositional modulated step-graded AlGaInxAs buffers grown on GaAs hold great promise to be virtual substrates of other metamorphic devices.

High performance transistors and photodetectors based on self-catalyzed zinc-blende InP nanowires

InP nanowires are an important material for nanoscale electronic and optical devices. However, the crystal phase mixing and stacking faults severely degrade the device's performance. Here, we demonstrate high performance field-effect transistors and photodetectors based on high-quality InP nanowires. The ⟨110⟩-oriented InP nanowires, which are formed by spontaneous kinking from the original ⟨111⟩ nanowire roots, exhibit a stacking-faults-free zinc blende crystal structure. Based on the high-quality nanowire, the field-effect transistor exhibits a high electron mobility of 1438 cm2 V−1 s−1, much higher than that with stacking faults. A high responsivity of 5495 A/W is obtained from the photodetector, among the highest values reported for InP nanowire photodetectors. Moreover, the response/recovery time of the device is only 0.6/2.2 ms, 2–3 orders of magnitude shorter than other InP nanowire photodetectors. The high crystal quality and excellent electrical and optical properties make the zinc blende ⟨110⟩ InP nanowire a promising candidate for high performance electronic and optoelectronic devices.

Telecom InP/InGaAs nanolaser array directly grown on (001) silicon-on-insulator.

A compact, efficient, and monolithically grown III-V laser source provides an attractive alternative to bonding off-chip lasers for Si photonics research. Although recent demonstrations of microlasers on (001) Si wafers using thick metamorphic buffers are encouraging, scaling down the laser footprint to nanoscale and operating the nanolasers at telecom wavelengths remain significant challenges. Here, we report a monolithically integrated in-plane InP/InGaAs nanolaser array on (001) silicon-on-insulator (SOI) platforms with emission wavelengths covering the entire C band (1.55μm). Multiple InGaAs quantum wells are embedded in high-quality InP nanoridges by selective-area growth on patterned (001) SOI. Combined with air-cladded InP/Si optical cavities, room-temperature operation at multiple telecom bands is obtained by defining different cavity lengths with lithography. The demonstration of telecom-wavelength monolithic nanolasers on (001) SOI platforms presents an important step towards fully integrated Si photonics circuits.

Nanostructured silicon substrates of nanopore morphology for buffer-layer free nanoheteroepitaxial growth of InP films

Enhanced stress relief via nanopores.

Room-temperature electrically-pumped 1.5 μm InGaAs/InAlGaAs laser monolithically grown on on-axis (001) Si.

Hetero-epitaxial growth of high quality InP on a complementary metal-oxide-semiconductor (CMOS)-compatible Si platform is compelling for monolithic integration of optoelectronics. It will provide the combined strength of mainstream mature InP-based photonic integrated circuits (PIC) technologies and large-volume, low-cost silicon-based manufacturing foundries. Direct monolithic integration of InP-based laser diodes (LDs) on silicon helps fully exploit the potential of silicon photonics and benefits the application of dense wavelength division multiplexing (DWDM) for telecommunications. Here, we report the first InGaAs/InAlGaAs multi-quantum-well (MQW) lasers directly grown on on-axis V-grooved (001) Si by metalorganic chemical vapor deposition (MOCVD). Lasing near 1.5 μm was achieved for the first time with a threshold current density Jth = 3.3 kA/cm2 under pulsed current injection at room temperature. A high characteristic temperature T0 of 133 K in the range of 20°C-40°C was measured. These results demonstrate the potential of adopting this large-area InP-on-Si substrate for integrating diverse III-V laser diodes, photodetectors, and high-frequency and high-speed transistors.

Epitaxial growth of high quality InP on Si substrates: The role of InAs/InP quantum dots as effective dislocation filters

Monolithic integration of InP on a Si platform ideally facilitates on-chip light sources in silicon photonic applications. In addition to the well-developed hybrid bonding techniques, the direct epitaxy method is spawning as a more strategic and potentially cost-effective approach to monolithically integrate InP-based telecom lasers. To minimize the unwanted defects within the InP crystal, we explore multiple InAs/InP quantum dots as dislocation filters. The high quality InP buffer is thus obtained, and the dislocation filtering effects of the quantum dots are directly examined via both plan-view and cross-sectional transmission electron microscopy, along with room-temperature photoluminescence. The defect density on the InP surface was reduced to 3 × 108/cm2, providing an improved optical property of active photonic devices on Si substrates. This work offers a novel solution to advance large-scale integration of InP on Si, which is beneficial to silicon-based long-wavelength lasers in telecommunications.

High performance photodetectors based on high quality InP nanowires**Project supported by the National Natural Science Foundation of China (Grant Nos. 51525202, 61574054, 61505051, and 61474040), the Science and Technology Plan of Hunan Province, China (Grant Nos. 2014FJ2001 and 2014TT1004), and the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China.

In this paper, small diameter InP nanowires with high crystal quality were synthesized through a chemical vapor deposition method. Benefitting from the high crystallinity and large specific surface area of InP nanowires, the simply constructed photodetector demonstrates a high responsivity of up to 1170 A·W−1 and an external quantum efficiency of 2.8×105% with a fast rise time of 110 ms and a fall time of 130 ms, even at low bias of 0.1 V. The effect of back-gate voltage on photoresponse of the device was systematically investigated, confirming that the photocurrent dominates over thermionic and tunneling currents in the whole operation. A mechanism based on energy band theory at the junction between metal and semiconductor was proposed to explain the back-gate voltage dependent performance of the photodetectors. These convincing results indicate that fine InP nanowires will have a brilliant future in smart optoelectronics.

Integration of High Quality III-V Materials on Si Using the Aspect-Ratio-Trapping Technique

III-V compound semiconductor materials grown on elemental semiconductor substrates have attracted much attention due to their mobility and direct bandstructure. And the III-V/Si system could combine the advantages of both material systems. The growth of high quality III-V thin films on Si (or Ge) is the first crucial step for III-V high-mobility or optical devices. However, The large lattice mismatch between III-V materials and Si is the main challenge for its integration on large sized Si wafers. Recently, the aspect-ratio trapping (ART) technique offers an elegant and cost effective solution for integrating III-V materials on the Si wafer. We report the selective area growth of III-V materials in “V-shaped” trenches on Si (001) substrates via metal-organic chemical vapor deposition (MOCVD).High quality GaAs thin films were achieved using a two-step growth process and the aspect ratio trapping method.In addition, high quality InP and InAs film was grown in trenches with a GaAs buffer layer. Material quality was confirmed by scanning electron microscope (SEM), transmission electron microscopy (TEM) and high resolution x-ray diffraction (HRXRD).This approach shows that these III-V materials could be high mobility channels for future CMOS technology node. We also report a InGaAs/InP multi-quantum-well growth in nanoscale V-shaped trenches on Si (001) substrate was studied using the aspect ratio trapping method. A high quality GaAs/InP buffer layer with two convex {111} B facets was selectively grown to promote the highly uniform, single-crystal ridge InP/InGaAs multi-quantum-well structure growth. Material quality was confirmed by transmission electron microscopy and room temperature micro-photoluminescence measurements. This approach shows great promise for the fabrication of photonics devices like nanolasers on Si substrate.