Recently, exciton-polaritons in a semiconductor microcavity were found to condense into a coherent ground state much like a Bose-Einstein condensate and a superfluid. They have become a unique testbed for generating and manipulating quantum vortices in a driven-dissipative superfluid. Here, we generate exciton-polariton condensate with nonresonant Laguerre-Gaussian (LG) optical beam and verify the direct transfer of light's

In this study, multicolor photodetectors (PDs) fabricated by using bulk p-i-n-based visible GaAs and near-infrared InGaAs structures were monolithically integrated through a high-throughput epitaxial lift-off (ELO) process. To perform multicolor detection in integrated structures, GaAs PDs were transferred onto InGaAs PDs by using a Y2O3 bonding layer to simultaneously detect visible and near-infrared photons and minimize the optical loss. As a result, it was found that the GaAs top PD and InGaAs bottom PD were vertically aligned without tilting in x-ray diffraction (XRD) measurement. A negligible change in the dark currents for each PD was observed in comparison with reference PDs through electrical characterization. Furthermore, through optical measurements and simulation, photoresponses were clearly revealed in the visible and near-infrared band for the material’s absorption region, respectively. Finally, we demonstrated the simultaneous multicolor detection of the visible and near-infrared region,which implies individual access to each PD without mutual interference. These results are a significant improvement for the fabrication of multicolor PDs that enables the formation of bulk-based multicolor PDs on a single substrate with a high pixel density and nearly perfect vertical alignment for high-resolution multicolor imaging.

No abstract

In this paper, InAsSb-based hetero-junction photovoltaic detector (HJPD) with an InAlSb barrier layer was grown on GaAs substrates. By using technology computer aided design (TCAD), a design of a barrier layer that can achieve nearly zero valance band offsets was accomplished. A high quality InAsSb epitaxial layer was obtained with relatively low threading dislocation density (TDD), calculated from a high-resolution X-ray diffraction (XRD) measurement. This layer showed a Hall mobility of 15,000 cm/V⋅s, which is the highest mobility among InAsSb layers with an Sb composition of around 20% grown on GaAs substrates. Temperature dependence of dark current, photocurrent response and responsivity were measured and analyzed for fabricated HJPD. HJPD showed the clear photocurrent response having a long cutoff wavelength of 5.35 μm at room temperature. It was observed that the dark current of HJPDs is dominated by the diffusion limited current at temperatures ranging from 200K to room temperature from the dark current analysis. Peak responsivity of HJPDs exhibited the 1.18 A/W and 15 mA/W for 83K and a room temperature under zero bias condition even without anti-reflection coating (ARC). From these results, we believe that HJPDs could be an appropriate PD device for future compact and low power dissipation mid-infrared on-chip sensors and imaging devices.

Although an InGaAs photo field-effect transistor (photo-FET) is a promising solution for high-performance photodetector due to its internal gain mechanism, the reported opto-electrical performance is limited by the low absorption caused by its thin body thickness and unoptimized electrical properties. To overcome this limitation, an InGaAs photo-FET with a metal gate reflector was demonstrated to achieve both high electrical and optical performance. We designed and optimized a metal-oxide-semiconductor (MOS) structure with the metal gate reflector by using numerical calculation and process optimization. Thanks to the optimization of both electrical and optical characteristics, the InGaAs photo-FETs were successfully demonstrated at the wavelengths of 1305 nm and 1550 nm. Therefore, this wafer-bonded InGaAs photo-FET with the metal gate reflector is a promising candidate for a high-performance and broad-band SWIR photodetector on a Si CMOS platform.