Light-Trapping Engineering for the Enhancements of Broadband and Spectra-Selective Photodetection by Self-Assembled Dielectric Microcavity Arrays

Abstract

Light manipulation has drawn great attention in photodetectors towards the specific applications with broadband or spectra-selective enhancement in photo-responsivity or conversion efficiency. In this work, a broadband light regulation was realized in photodetectors with the improved spectra-selective photo-responsivity by the optimally fabricated dielectric microcavity arrays (MCAs) on the top of devices. Both experimental and theoretical results reveal that the light absorption enhancement in the cavities is responsible for the improved sensitivity in the detectors, which originated from the light confinement of the whispering-gallery-mode (WGM) resonances and the subsequent photon coupling into active layer through the leaky modes of resonances. In addition, the absorption enhancements in specific wavelength regions were controllably accomplished by manipulating the resonance properties through varying the effective optical length of the cavities. Consequently, a responsivity enhancement up to 25% within the commonly used optical communication and sensing region (800 to 980 nm) was achieved in the MCA-decorated silicon positiveintrinsic-negative (PIN) devices compared with the control ones. This work well demonstrated that the leaky modes of WGM resonant dielectric cavity arrays can effectively improve the light trapping and thus responsivity in broadband or selective spectra for photodetection and will enable future exploration of their applications in other photoelectric conversion devices.

Near Infrared Efficiency Enhancement of Silicon Photodiodes by Integration of Metal Nanostructures Supporting Surface Plasmon Polaritrons

“…Recently, other approaches have been proposed by the scientific community: i) light trapping (by means of nanotexturing) [6]; ii) integration with photonic structures (metalenses or metasurfaces) [7], or iii) integration with metal nanostructures supporting plasmonic resonances, [8]. Among the others, a proposed solution is the integration of thin photodetectors with a nanostructure supporting Surface Plasmon Polaritons (SPP) able to provide light confinement and a subsequent enhancement of the light absorption in subwavelength regions.…”

Optical Resonator Enhanced Photovoltaics and Photocatalysis: Fundamental and Recent Progress

“…Several solar cells based on the WGM cavity array have been demonstrated in the past few years. [20,21,[129][130][131][132] Over the past few years, Sudakar's group has demonstrated and investigated the impact of WGM resonance effect on dye-sensitized solar cells (DSSCs), [133] quantum dot sensitized solar cells, [134] and CdS-CuInS 2 thin film sensitized solar cells. [135] Most of the work was done be using microspheres, which is the most simple form of WGM microcavity.…”

“…Taking advantage of the unique optical properties, such as high-quality factor (Q-factor) and small mode volume, optical resonators offer a promising platform to enhance the lightmatter interactions in many areas, such as lasers, integrated photonics, photodetectors, optical sensors, biomedical detection, and photoenergy-related devices. [8][9][10][11][12][13][14][15][16] To date, many types of optical resonators have been applied in both photovoltaic and photocatalysis, including Fabry-Perot (FP) cavities, [17][18][19] whispering gallery mode (WGM) cavities, [20][21][22] photonic crystal (PC) cavities, [23][24][25] plasmonic resonators (Figure 1). [26][27][28] From an optics point of view, these optical resonant configurations exhibit strong optical feedback and photons confinement, which has the great potential to solve the intrinsic tradeoff between light absorption and carrier diffusion.…”

Near Infrared Efficiency Enhancement of Silicon Photodiodes by Integration of Metal Nanostructures Supporting Surface Plasmon Polaritrons

“…Recently, other approaches have been proposed by the scientific community: (i) light trapping (by means of nanotexturing) [ 10 ]; (ii) integration with photonic structures (metalenses or metasurfaces) [ 11 ], or (iii) integration with metal nanostructures supporting plasmonic resonances, [ 12 , 13 ]. Among the others, a very interesting proposed solution is the integration of thin photodetectors with a nanostructure supporting surface plasmon polaritons (SPP) able to confine the light in a sub-wavelength region at the detector surface, with a subsequent absorption enhancement.…”