Shiwei Cai

Monolithically Integrated Photodetector Array With a Multistep Cavity for Multiwavelength Receiving Applications

A monolithically integrated photodetector array used for multiwavelength receiving was realized by growth of an InP-In0.53Ga0.47As-InP p-i-n structure on a GaAs/AlGaAs Fabry-Perot filter. The filter with a multistep cavity was fabricated by wet etching and regrowth. Each photodetector in the array detects a different wavelength, so the array functions as a multiwavelength receiver. The high-quality GaAs/InP heteroepitaxy was realized by employing a thin low temperature buffer layer. The photodetector array detects four wavelength channels, whose interval is about 10 nm , around 1550 nm. A full-width half-maximum less than 0.5 nm , a peak quantum efficiency over 15%, and a 3-dB bandwidth of 9 GHz were simultaneously obtained in the photo-detector array.

Monothically Integrated Long-Wavelength Tunable Photodetector

This paper demonstrated a tunable long-wavelength photodetector by using the heteroepitaxy growth of InP-In0.53Ga0.47As-InP p-i-n structure on a GaAs-based GaAs/AlAs Fabry-Perot filter structure. High-quality heteroepitaxy was realized by employing a thin low-temperature buffer layer. A wavelength tuning range of 10.0 nm, an external quantum efficiency of about 23%, a spectral linewidth of 0.8 nm, and a 3-dB bandwidth of 6.2 GHz were simultaneously obtained in the device.

Long Wavelength Multiple Resonant Cavities RCE Photodetectors on GaAs Substrates

A 1550-nm high-speed, high efficiency, and narrow-linewidth resonant cavity enhanced photodetector with three resonant cavities is demonstrated. The photodetector, operating at a long wavelength, is monolithically integrated by using a heteroepitaxy growth of an InP-based p-i-n structure on the GaAs-based multiple resonant cavities. High-quality heteroepitaxy was realized by employing a thin low-temperature buffer layer. A peak quantum efficiency value of 70%, a spectral response linewidth less than 0.75 nm (full-width at half-maximum), and a 3-dB bandwidth of 36 GHz were simultaneously obtained in the device.

A Novel Hybrid Integrated Photodetector Based on a Cone Absorption Cavity

A novel hybrid integrated photodetector with flat-top steep-edge spectral response, which consists of a Si-based multi-cavity Fabry-Pérot (F-P) filter and an InP-based cone absorption cavity (with a 0.2 m In0.53Ga0.47As absorption layer), has been designed and fabricated. The operating lightwave is well confined to the cone absorption, and experiences multiple reflections across the absorption layer. Thus, an absorption enhancement effect without resonance can be achieved. Based on multi-cavity F-P structure and a cone cavity, this device can get good flat-top steep-edge spectral response and high quantum efficiency. The photodetector is fabricated by bonding a Si-based multi-cavity F-P filter with an InP-based cone absorption cavity. An integrated device with a peak quantum efficiency of 60% around 1550 nm, the dB band of 0.5 nm, and the 25 dB band of 1.06 nm, is simultaneously obtained.

A Monothically Integrated Dual-Wavelength Tunable Photodetector Based on a Taper GaAs Substrate

The design and fabrication of a monolithically integrated dual-wavelength tunable photodetector are reported. The dual-wavelength character is realized by fabricating a taper substrate. The photodetector, operating at a long wavelength, is monolithically integrated by using a heteroepitaxy growth of InP-In0.53Ga0.47As-InP p-i-n structure on a GaAs-based GaAs/ AlAs Fabry-Perot-filter structure, which can be tuned via the thermal-optic effect. High-quality heteroepitaxy was realized by employing a thin low-temperature buffer layer. The integrated device with a dual-peak distance of 7 nm (1530, 1537 nm), a wavelength-tuning range of 5.0 nm, and a 3-dB bandwidth of 5.9 GHz was demonstrated, agreeing with the theoretical simulation.

Quantum efficiency enhanced InGaAs/InP photodetector with polarization insensitive subwavelength gratings

A polarization insensitive periodical subwavelength grating and a photodetector incorporating this grating were proposed and fabricated. The quantum efficiency of the photodetector was improved 50% by incorporating an achieved grating with more than 80% reflectivity.

The LP-MOCVD growth of BGaAs alloys with different gallium precursors

BGaAs alloys have been grown on GaAs substrate with different Ga precursor, TMGa and TEGa. With TEGa, it can grow at a lower temperature, and obtain a higher boron content than that grown with TMGa.

High-Efficiency Planar InGaAs Photodetector

A high-efficiency planar vertical-illuminated photodetector (VPD) was fabricated. The 3-dB bandwidth was 8.5 GHz at 1550 nm. The experimental measurement results obtained good agreement with simulation results.

Growth and Characterization of GaAs/AlGaAs Core-Multishell Nanowires by Metalorganic Chemical Vapor Deposition

We have investigated the growth and photoluminescence (PL) characteristics of GaAs/AlGaAs core-multishell nanowires (NWs). Theses NWs are grown by means of vapor-liquid-solid (VLS) method for cores growth and metalorganic chemical vapor deposition (MOCVD) for multishell growth on GaAs (111)B substrate. The crystallographic quality is perfect in the body of GaAs/AlGaAs core-multishell NWs and a small axial elongation with some defects at the top of NWs was also achieved. The PL spectra reveal that GaAs/AlGaAs core-multishell NWs have much higher optical efficiency than bare GaAs NWs.

Study on Wavelength-Tunable Photodetector with Surface Plasma Wave Excitation Filter

Surface plasma wave excitation filters is used in the new photodetector in this paper. The detectivity is enhanced by excitation of surface plasma waves (SPWs) using a Metal Aperture Arrays grating. A bias-tunable broadband response is achieved.