Investigation Of Novel Micro-And Nano-Structures And Silicon-Based Ⅲ-ⅤSemiconductor Photodetectors

With the rapid development of optical communication, high-performance semiconductor optoelectronic devices with multifunction integrated are highly desirable. Ⅲ-Ⅴ semiconductor photodetectors which convert optical power to electrical energy are widely used in optical communication systems. Therefore, how to further realize the Ⅲ-Ⅴ semiconductor photodetector with multifunction integrated is a crucial scientific issue during the development history of optical communication.In recent years, some new type nanophotonic structures such as microring resonator, subwavelength gratings, have been extensively studied and employed as fundamental elements of silicon-based photonic integration circuits. Furthermore, monolithic and hybrid integration of Ⅲ-Ⅴ/Si semiconductor material are developing very fast. Development of silicon-based photonic integration technology paves the way for realization of the Ⅲ-Ⅴ semiconductor optical detector performance and multi-functional. Naturally, how to use Si-based nano-structures to improve the performance of Ⅲ-Ⅴ semiconductor photodetectors becomes very important.The reaserch of this thesis is focusing on the subwavelength gratings and microring resonators. The main purpose of this work is to realize high-performance and multifunctional photodecters operating at long wavelength by employing silicon nano/micro structures including microring resonators and subwavelength gratings. The main contants and innovations are listed as follows:1. A new model is presented for investigating Fano resonance in subwavelength resonant grating structures. The core idea is to combine the reflection spectrum with the grating structure by using the eigen modes as a bridge. We compared our reflection spectrum with RCWA simulation results. As a result, the calculated resonant wavelengths of two simulations agree well with each other in the linear shape region. At last, we present a new type high-contrast resonant grating structure to validate our model.2. A bandwidth tunable filter structure, which is based on subwavelength high contrast grating structure with single layer was proposed and designed. Theoretical studies indicate that the incident angle can control the bandwidth of the filter, and the device temperature tolerance is within6K. The transmission spectrum of the grating is not sensitive to the change of cross section shape under certain condition.3. A new method, which is based on the optical resonance of subwavelength resonant grating, for regulating optical properties of graphene is proposed. A grapheme absorber with multilayer subwavelength grating structure was designed and simulated. Theoretical studies show that the multilayer subwavelength grating structure can control the line shape of the graphene absorption spectrum. The multilayer subwavelength grating structure allows the absorption spectrum of graphene to be more selective about the incident angle. The absorption peak shifts and the spectral bandwidth increases along with the increase of the incident angle.4. A broadband quantum-efficiency enhanced InGaAs/InP PIN photodetector integrated with silicon resonant waveguide gratings was proposed. The physical principle of photodector is studied. We then design and fabricate an InGaAs/InP PIN photodetector assembled with silicon resonant waveguide grating. The measured results show that quantum efficiency of the photodetector with silicon resonant waveguide gratings can be increased by31.6%compared to that without silicon resonant waveguide gratings at the wavelength range of1500nm to1600nm for TE-polarization. The photodetector showed the dark current of27nA at a reverse bias of-3.0V with The3dB bandwidth of10GHz.5. A hybrid integrated polarization dependent photodetector was fabricated successfully, which is realized by integrating a silicon resonant waveguide grating with an InGaAs/InP PIN photodetector. We design and fabricate a broadband silicon resonant grating with polarization selectivity, and it then was integrated with InGaAs/InP PIN absorbtion structure by BCB bonding processing. The measured results show that the dark current of27nA at a reverse bias of-3.0V and the qutuam efficiency of the photodetecotor are25%and2%for TM-polarization and TE-polarization, respectively at the wavelength range of1500nm to1600nm for TM-polarization. The3dB bandwidth of the photodetector was9GHz.6. A wavelength selective waveguide photodetector was proposed, which is realized by integrating silicon microring filter and InGaAsP waveguide photodetector. The physical principles of microring and waveguide photodetector are both studied. The silicon microring filter and InGaAsP waveguide photodetector were designed and fabricated. Next, a micro-assembly platform was set up for assembling silicon passivce waveguide devices and Ⅲ-Ⅴ waveguide photodetectors. The two devices were then intergrated by BCB bonding process. Experimental results show that the free spspectral range and linewidth of the responance are7nm and4nm, resespectivly, the dark current of the photodector is250nA at a reverse bias of-3.0V and the responsivity of the photodetecotor in through port was0.002A/W at wavelength of1555nm.7. A new type photodetector with a flat-top steep-edge response composed of cascaded microring resonators on silicon-on-insulator was proposed to improve the tolerance of signal wavelength drift in optical communication. For the photodetector, polarization insensitively cascaded silicon microring resonators are employed as optical filter cavity, and a silicon racetrack resonator bonded in a p-i-n chip as optical detecting cavity. With optimizing parameters, the photodetector showed that the maximum quantum efficiency can reach by98%with the3dB bandwidth of0.2nm and the flatness coefficient of0.56.