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1.
Nanotechnology ; 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32392551

RESUMO

We report on multi-stacked InAs/GaSb nano-ridges directly grown on (001) patterned Si substrates by metal-organic chemical vapor deposition (MOCVD). Uniform GaSb and InAs nano-ridges were demonstrated with optimized growth parameters. By adjusting the switching sequences, we also obtained defect-free InAs/GaSb and GaSb/InAs interfaces. Based on these fine-tuned growth conditions, multi-stacked InAs/GaSb nano-ridges were developed and characterized. The nano-ridges showed uniform morphology from scanning electron microscopy (SEM), and no observable crystalline defects were detected at the hetero-interfaces by transmission electron microscopy (TEM). These InAs/GaSb nano-ridges show great potential for applications in nano-scale tunneling devices and long wavelength light emitters and detectors. The demonstrated growth techniques provide helpful insights for the growth process control of 6.1 Å family compound semiconductors directly on Si by MOCVD.

2.
Opt Lett ; 44(18): 4566-4569, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31517932

RESUMO

Directly grown quantum dot (QD) lasers on silicon are appealing for monolithic integration of photonic circuits from a technoeconomic perspective. In this Letter, we report miniaturization of these Si-based lasers employing high-quality whispering-gallery mode microresonators. Based on previously developed InAs/InAlGaAs QDs on the complementary metal-oxide-semiconductor-standard (001) Si platform and optimized device implementation techniques, on-chip electrically pumped InP-based QD microring lasers (MRLs) on Si are successfully realized for the first time. Room-temperature pulsed lasing in the 1.5 µm wavelength band, with a threshold of 50 mA, is measured for 50-µm-diameter MRLs. Lasing up to 70°C is achieved with a characteristic temperature of 51.5 K.

3.
Opt Lett ; 44(4): 767-770, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30767982

RESUMO

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 (1.55 µm). 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.

4.
Nano Lett ; 18(9): 5640-5645, 2018 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-30139259

RESUMO

van der Waals heterostructures that are usually formed using atomically thin transition-metal dichalcogenides (TMDCs) with a direct band gap in the near-infrared to the visible range are promising candidates for low-dimension optoelectronic applications. The interlayer interaction or coupling between two-dimensional (2D) layer and the substrate or between adjacent 2D layers plays an important role in modifying the properties of the individual 2D material or device performances through Coulomb interaction or forming interlayer excitons. Here, we report the realization of quasi-zero-dimensional (0D) photon emission of WS2 in a coupled hybrid structure of monolayer WS2 and InGaN quantum dots (QDs). An interfacially bound exciton, i.e., the coupling between the excitons in WS2 and the electrons in QDs, has been identified. The emission of this interfacially bound exciton inherits the 0D confinement of QDs as well as the spin-valley physics of excitons in monolayer WS2. The effective coupling between 2D materials and conventional semiconductors observed in this work provides an effective way to realize the 0D emission of 2D materials and opens the potential of compact on-chip integration of valleytronics and conventional electronics and optoelectronics.

5.
Opt Lett ; 43(14): 3401-3404, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30004516

RESUMO

We report for the first time on-chip integration of III-nitride voltage-controlled light emitters with visible and ultraviolet (UV) photodiodes (PDs). InGaN/GaN and AlGaN/GaN heterostructures were grown in specific regions by selective-area epitaxy, allowing monolithic integration of versatile devices including visible light emitting diodes (LEDs), visible-light PDs, AlGaN/GaN high electron mobility transistors (HEMTs), and UV-light Schottky barrier (SB) PDs. A serial connection between the LED and HEMT through the epitaxial layers enables a three-terminal voltage-controlled light emitter (HEMT-LED), efficiently converting voltage-controlled signals into visible-light signals that can be coupled into an adjacent visible-light PD generating electrical signals. While the integrated blue HEMT-LED and PD transmits signals carried by visible light, the visible-blind SB-PD on a chip receives external UV light control signals with negligible interference from the on-chip visible-light source. This integration scheme can be extended to open an avenue for developing a variety of applications, such as smart lighting, on-chip optical interconnect, optical wireless communication, and opto-isolators.

6.
Opt Express ; 26(11): 14514-14523, 2018 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-29877487

RESUMO

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.

7.
Nanotechnology ; 29(22): 225601, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29517486

RESUMO

We report the growth of vertically stacked InGaAs/InP quantum wires on (001) Si substrates with adjustable room-temperature emission at telecom bands. Based on a self-limiting growth mode in selective area metal-organic chemical vapor deposition, crescent-shaped InGaAs quantum wires with variable dimensions are embedded within InP nano-ridges. With extensive transmission electron microscopy studies, the growth transition and morphology change from quantum wires to ridge quantum wells (QWs) have been revealed. As a result, we are able to decouple the quantum wires from ridge QWs and manipulate their dimensions by scaling the growth time. With minimized lateral dimension and their unique positioning, the InGaAs/InP quantum wires are more immune to dislocations and more efficient in radiative processes, as evidenced by their excellent optical quality at telecom-bands. These promising results thus highlight the potential of combining low-dimensional quantum wire structures with the aspect ratio trapping process for integrating III-V nano-light emitters on mainstream (001) Si substrates.

8.
Opt Express ; 25(25): 31281-31293, 2017 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-29245805

RESUMO

In this paper, we present a parametric study of high performance microdisk lasers at 1.55 µm telecom wavelength, monolithically grown on on-axis (001) Si substrates incorporating quantum dots (QDs) as gain elements. In the optimized structure, seven layers of QDs were adopted to provide a high gain as well as a suppressed inhomogeneous broadening. The same laser structure employing quantum wells (QWs) on Si was concurrently evaluated, showing a higher threshold and more dispersive quantum efficiency than the QDs. Finally, a statistical comparison of these Si-based QD microdisk lasers with those grown on InP native substrates was conducted, revealing somewhat higher thresholds but of the same order. The monolithically grown QD microlasers on Si also demonstrated excellent temperature stability, with a record high characteristic temperature of 277 K. This work thus offers helpful insight towards the optimization of reliable Si-based QD lasers at 1550 nm.

9.
Opt Express ; 25(22): 26853-26860, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29092170

RESUMO

We report statistical comparisons of lasing characteristics in InAs quantum dot (QD) micro-rings directly grown on on-axis (001) GaP/Si and V-groove (001) Si substrates. CW thresholds as low as 3 mA and high temperature operation exceeding 80 °C were simultaneously achieved on the GaP/Si template template with an outer-ring radius of 50 µm and a ring width of 4 µm, while a sub-milliamp threshold of 0.6 mA was demonstrated on the V-groove Si template with a smaller cavity size of 5-µm outer-ring radius and 3-µm ring width. Evaluations were also made with devices fabricated simultaneously on native GaAs substrates over a significant sampling analysis. The overall assessment spotlights compelling insights in exploring the optimum epitaxial scheme for low-threshold lasing on industry standard Si substrates.

10.
Opt Express ; 25(22): 27715-27723, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29092242

RESUMO

We report InAs/InGaAs quantum dot (QD) waveguide photodetectors (PD) monolithically grown on silicon substrates. A high-crystalline quality GaAs-on-Si template was achieved by aspect ratio trapping together with the combined effects of cyclic thermal annealing and strain-balancing layer stacks. An ultra-low dark current of 0.8 nA and an internal responsivity of 0.9 A/W were measured in the O band. We also report, to the best of our knowledge, the first characterization of high-speed performance and the first demonstration of the on-chip photodetection for this QD-on-silicon system. The monolithically integrated waveguide PD shares the same platform as the previously demonstrated micro-ring lasers and can thus be integrated with laser sources for power monitors or amplifiers for pre-amplified receivers.

11.
Opt Express ; 25(4): 3927-3934, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28241602

RESUMO

High performance III-V lasers at datacom and telecom wavelengths on on-axis (001) Si are needed for scalable datacenter interconnect technologies. We demonstrate electrically injected quantum dot lasers grown on on-axis (001) Si patterned with {111} v-grooves lying in the [110] direction. No additional Ge buffers or substrate miscut was used. The active region consists of five InAs/InGaAs dot-in-a-well layers. We achieve continuous wave lasing with thresholds as low as 36 mA and operation up to 80°C.

12.
Opt Lett ; 42(4): 679-682, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28198838

RESUMO

InAs/InAlGaAs quantum dot active layers within microcavity resonators offer the potential of ultra-low-threshold lasing in the 1.55 µm telecom window. Here, we demonstrate the first quantum dot microdisk laser with single-mode emission around 1.55 µm under continuous-wave optical pumping up to 170 K. The extracted threshold is as low as 32 µW at 77 K. This result lays the foundation of an alternative to quantum-well microlasers for low-threshold and highly compact monolithically integratable light emitting sources in fiber communication.

13.
Opt Express ; 24(18): 21038-45, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27607707

RESUMO

We report comparison of lasing dynamics in InAs quantum dot (QD) micro-disk lasers (MDLs) monolithically grown on V-groove patterned and planar Si (001) substrates. TEM characterizations reveal abrupt interfaces and reduced threading dislocations in the QD active regions when using the GaAs-on-V-grooved-Si template. The improved crystalline quality translates into lower threshold power in the optically pumped continuous-wave MDLs. Concurrent evaluations were also made with devices fabricated simultaneously on lattice-matched GaAs substrates. Lasing behaviors from 10 K up to room temperature have been studied systematically. The analyses spotlight insights into the optimal epitaxial scheme to achieve low-threshold lasing in telecommunication wavelengths on exact Si (001) substrates.

14.
Opt Lett ; 41(7): 1664-7, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27192313

RESUMO

Direct integration of high-performance laser diodes on silicon will dramatically transform the world of photonics, expediting the progress toward low-cost and compact photonic integrated circuits (PICs) on the mainstream silicon platform. Here, we report, to the best of our knowledge, the first 1.3 µm room-temperature continuous-wave InAs quantum-dot micro-disk lasers epitaxially grown on industrial-compatible Si (001) substrates without offcut. The lasing threshold is as low as hundreds of microwatts, similar to the thresholds of identical lasers grown on a GaAs substrate. The heteroepitaxial structure employed here does not require the use of an absorptive germanium buffer and/or dislocation filter layers, both of which impede the efficient coupling of light from the laser active regions to silicon waveguides. This allows for full compatibility with the extensive silicon-on-insulator (SOI) technology. The large-area virtual GaAs (on Si) substrates can be directly adopted in various mature in-plane laser configurations, both optically and electrically. Thus, this demonstration represents a major advancement toward the commercial success of fully integrated silicon photonics.

15.
Opt Express ; 23(25): 32504-15, 2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26699040

RESUMO

Colloidal quantum dots which can emit red, green, and blue colors are incorporated with a micro-LED array to demonstrate a feasible choice for future display technology. The pitch of the micro-LED array is 40 µm, which is sufficient for high-resolution screen applications. The method that was used to spray the quantum dots in such tight space is called Aerosol Jet technology which uses atomizer and gas flow control to obtain uniform and controlled narrow spots. The ultra-violet LEDs are used in the array to excite the red, green and blue quantum dots on the top surface. To increase the utilization of the UV photons, a layer of distributed Bragg reflector was laid down on the device to reflect most of the leaked UV photons back to the quantum dot layers. With this mechanism, the enhanced luminous flux is 194% (blue), 173% (green) and 183% (red) more than that of the samples without the reflector. The luminous efficacy of radiation (LER) was measured under various currents and a value of 165 lm/Watt was recorded.

16.
Opt Lett ; 37(19): 4035-7, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23027270

RESUMO

We report silicon waveguide butt-coupled p-i-n InGaAs photodetectors epitaxially grown on silicon-on-insulator substrates by metalorganic chemical vapor deposition. The InGaAs absorption layer that is lattice-matched to InP is selectively grown on patterned SOI substrates, employing metamorphic growth of GaAs and InP buffer layers. We measure a dark current of 2.5 µA and a responsivity of 0.17 A/W at 1550 nm wavelength upon -1 V bias voltage, with a 20 µm × 20 µm InGaAs photodetector area. This device exhibits a 3 dB bandwidth of 9 GHz upon -4 V bias voltage. We demonstrate an open-eye diagram at 10 Gb/s data rate upon -4 V bias voltage.

17.
Opt Express ; 19 Suppl 4: A956-61, 2011 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-21747567

RESUMO

LEDs on Si offer excellent potential of low cost manufacturing for solid state lighting and display, taking advantage of the well-developed IC technologies of silicon. In this paper, we report how the performance of LEDs grown on Si can be improved. Multiple quantum well InGaN LED structure was grown on patterned silicon substrates and circular LEDs 160 µm in radius were processed. Fabricated LEDs were then transferred to an electroplated copper substrate with a reflective mirror inserted by a double-flip transfer process, to improve the light extraction efficiency and heat dissipation. The light output power of LEDs on copper increased by ~80% after the transfer. The operating current before the onset of light output power saturation also increased by 25% because of the good thermal conductivity of copper. The light output power of packaged LEDs on copper was 6.5 mW under 20 mA current injection and as high as 14 mW driven at 55 mA.

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