Junping Mi

Ridge InGaAs/InP multi-quantum-well selective growth in nanoscale trenches on Si (001) substrate

Metal organic chemical vapor deposition of InGaAs/InP multi-quantum-well in nanoscale V-grooved 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 and nanolasers on Si substrate.

1.06-μm InGaAs/GaAs multiple-quantum-well optical thyristor lasers with a PiNiN structure.

InGaAs/GaAs multiple quantum well (MQW)-depleted optical thyristor lasers operating at 1.06 μm with a waveguide-type PiNiN structure is presented for the first time. The optical thyristor lasers clearly show nonlinear S-shaped current-voltage and lasing characteristics. The measured switching voltage and current are 5 V and 1 mA, respectively. The holding voltage and current are 2.6 V and 3.6 mA, respectively. A relatively high output light power of 30 mW per facet at room temperature is achieved. The lasing wavelength is 1.055 μm at a bias current of 80 mA at 25 °C.

A Directional-Emission 1060-nm GaAs/InGaAs Microcylinder Laser

A GaAs/InGaAs microcylinder laser in diameter of 15 μm connected with a 2-μm wide output waveguide is fabricated using standard photolithography and inductively coupled plasma etching technique. With the output waveguide, we realize the directional emission with the pulsed lasing operation wavelength of 1060 nm at room temperature. The maximum output power is ~6 μW and the minimum threshold current is 2 mA, which is comparatively low compared with previous reported GaAs material microlasers. A single mode operation is achieved near threshold current at the wavelength of 1060 nm. Mode characteristics are calculated and analyzed by 2-D finite-difference time-domain simulation. The small volume, low threshold current, and low energy consumption make the GaAs/InGaAs microcylinder laser we presented a promising light source for optical interconnection on chip.

A Hybrid Single-Mode Laser Based on Slotted Silicon Waveguides

An InGaAsP-Si hybrid single-mode laser based on etched slots in silicon waveguides was demonstrated operating at 1543 nm. The InGaAsP gain structure was bonded onto a patterned silicon-on-insulator wafer by selective area metal bonding method. The mode-selection mechanism based on a slotted silicon waveguide was applied, in which the parameters were designed using the simulation tool cavity modeling framework. The III-V lasers employed buried ridge stripe structure. The whole fabrication process only needs standard photolithography and inductively coupled plasma etching technology, which reduces cost for ease in technology transfer. At room temperature, a single mode of 1543-nm wavelength at a threshold current of 21 mA with a maximum output power of 1.9 mW in continuous-wave regime was obtained. The side mode suppression ratio was larger than 35 dB. The simplicity and flexibility of the fabrication process and a low cost make the slotted hybrid laser a promising light source.

A GaAs-Based Hybrid Integration of a Tunneling Diode and a 1060-nm Semiconductor Laser

We report on a hybrid integrated tunneling diode, with a simple structure, and a quantum well laser diode, lasing at ~1060 nm, on GaAs substrate. The low-frequency operation of the integrated circuit was measured and obvious negative differential resistance regions were shown in the electrical and optical output. The electrical and optical bistability were measured, and the peak and valley voltage were 2.03 and 2.17 V, respectively. A 140-mV-wide hysteresis loop and an optical on/off ratio of 21 dB were obtained. The device has potential applications in biomedicine and optical interconnects.

Nanoscale spatial phase modulation of GaAs growth in V-grooved trenches on Si (001) substrate*

This letter reports the nanoscale spatial phase modulation of GaAs growth in V-grooved trenches fabricated on a Si (001) substrate by metal–organic vapor-phase epitaxy. Two hexagonal GaAs regions with high density of stacking faults parallel to Si {111} surfaces are observed. A strain-relieved and defect-free cubic phase GaAs was achieved above these highly defective regions. High-resolution transmission electron microscopy and fast Fourier transforms analysis were performed to characterize these regions of GaAs/Si interface. We also discussed the strain relaxation mechanism and phase structure modulation of GaAs selectively grown on this artificially manipulated surface.

Hybrid integration of a tunneling diode and a 1060-nm semiconductor laser

We report on a hybrid integrated tunneling diode, with a simple structure, and a quantum well laser diode, lasing at around 1060 nm, on GaAs substrate. The basic DC-characteristics of the integrated circuit was measured and analyzed. Obvious negative differential resistance regions were shown in the electrical and optical output. The device has potential applications in biomedicine and optical interconnects.

Fabrication of InGaAs/InP DBR laser with butt-coupled passive waveguide utilizing selective wet etching

We investigated the etching process especially for the integrated InGaAs/InP multiquantum-well laser. Two different ways of etching process were demonstrated, which are RIE followed by selective wet etching and selective wet etching only. The latter one showed ideal interface between active region and passive waveguide after regrowth. This etching process is simpler and more effective than the first one. Using this process, we also fabricated a 1.79-μm DBR laser with 350-μm active region and 400-μm passive waveguide. The output power and threshold current and were demonstrated as a function of temperature. The wavelength tuning characters were investigated with current and temperature changes. It is demonstrated that this etching process can be successfully used to fabricate integrated photonic devices with InGaAs/InP materials and the DBR laser can be a candidate for gas sensing system due to the single mode and large tuning range.

High quality GaAs nanowires epitaxy on patterned Si substrates

Epitaxial growth of III-V compound semiconductors on Si has attracted significant attention for many years due to the potential for monolithic integration of III-V based optoelectronic devices with Si integrated circuits. There are three major problems for GaAs monolithic epitaxy on Si, respectively the large lattice mismatch, the difference in thermal expansion coefficient, and growth of a polar material on a nonpolar substrate. Various dislocation reduction techniques have been proposed, such as graded SiGe buffer layers, thermal cycles annealing (TCA), and strained-layer superlattices (SLs) as dislocation filters. Unfortunately, these methods generally require relatively thick epitaxial layers and/or complex epitaxial process. This study relates to the heteroepitaxy of GaAs on nanopatterned Si substrates using the selective aspect ratio trapping method. The dislocations originally generated at the GaAs/Si interface are mostly isolated by the SiO2 side wall. High-quality GaAs nanowires have been grown on Si(001) substrates by metal-organic chemical vapor deposition. A method of two-step epitaxy of GaAs is performed to achieve a high-quality GaAs layer with a 217 arcsec narrow FWHM of HRXRD. Material quality was confirmed by Scanning electron microscope (SEM) and transmission electron microscopy (TEM). We also simulated the distribution of the light field on the nanoscale GaAs layer surround by Ag films used the FDTD method. The light field confined well in the 250nm width GaAs nanowire which can be used in the nanolasers on Silicon as light sources.