In order to improve the fabrication robustness of the inverse-designed devices that have complex topology structures, we propose an optimization technique, named as structure transformation (ST), to transform structures of the inverse-designed devices into simple topologies that contain less irregularly tiny features, sharp corners and less boundary regions. The proposed ST technique, based on a new alternately-implementing strategy of optical performance optimization and modified curvature-constrained structure adjustment, effectively facilitates an overall simplification of the structure topologies of devices, enhances their robustness to fabrication uncertainties, and simultaneously maintains or even improves their optical performances. To verify the feasibility of the technique, three types of typical SOI-based devices (T-junction, 1×3 power splitter and 90º crossing) with and without ST were designed, among which the ones without ST were given as control groups. Thanks to the ST, the boundary regions and highly curved ranges in these devices are all significantly reduced, while their performances are well maintained or even improved. Next, the effect of the ST on fabrication tolerances were investigated, and the simulation results show that the devices with ST are more robust to over/under-etching errors than the control groups. At last, the T junction and 1×3 power splitter and their control groups were fabricated each with 6 samples. Measured results show that the performances of the devices with ST deviate from the simulated performances much less than their control groups, which agrees well with the simulated results in fabrication tolerances investigation. Summarily, we proposed and demonstrated a technique that provides the inverse-designed devices new possibilities to achieve simpler topologies with better fabrication robustness and improved performances at the same time.

In this study, we propose a centrifugation packaging (CP) structure to enhance the optical and thermal dissipation performance of LEDs, using SBA-15 particles to facilitate the sedimentation and dispersion of QDs. The results indicate that the EL spectra of the LEDs remains almost unchanged after the centrifugation time of 60 min and a CP structure can be obtained. The radiation power and luminous flux of LEDs with a CP structure improve by 9.1% and 10.4%, respectively, compared with the uniform distribution (UD) structure. The surface temperature of LED devices with the CP structure is reduced to 34.4 °C from 41.8 °C at a current of 100 mA. Furthermore, the simulation results show that the maximum temperature in the CP structure is 22.4% lower than that in the UD structure at a current of 500 mA. Thus, this study can provide a new perspective for designing settlement structures of QD-LEDs to enhance their optical and thermal performance.

The development of solution-processed hybrid organic-inorganic heterojunction solar cells have provoked increasing research effort due to potential to significantly reduce the fabrication cost of semiconductor solar cells while maintaining the high power conversion efficiency (PCE). With a recent record of GaAs solar cells achieving 28.8% via a wafer lift-off technique, hybrid organic/GaAs solar cells can offer an alternative route to provide more affordable solar power than current semiconductor technologies. In this work, we demonstrate the hybrid devices based on a conductive polymer poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) directly spun-cast on planar gallium arsenide materials. While still lacking for optimized antireflection, the PCE of the best performing device can achieve nearly 10% by introducing the monolayer graphene as transparent electrode. The current progress presents 2-fold enhancement in comparison to a previous record at 5% based on GaAs nanowire templates.

Inverse-designed devices with thousands of degrees of freedom could achieve high performance in compact footprints, but typically have complex structure topologies that contain many irregular and tiny features and sharp corners, which tend to lead to a poor robustness to fabrication errors. In order to effectively transform the structure of inverse-designed nanophotonic devices into simple structure topologies that have high robustness to fabrication errors without sacrificing device performance, in this paper, we propose a structure adjustment method that innovatively adjusts the structures of inverse-designed devices by introducing their structural sensitivity to the optical performance, extracting the device substructures with high sensitivity and eliminating those with low sensitivity, and, finally, transforming the device structures into simple structure topologies with high robustness and better performance. Two devices (90° crossing and T-junction) were designed and fabrication tolerance simulation was conducted to verify the method. The results show that the devices designed using the proposed method achieved better performance and were more robust to under/over-etched errors.