Black GaAs: Gold-Assisted Chemical Etching for Light Trapping and Photon Recycling

Plasma-Etched Black GaAs Nanoarrays with Gradient Refractive Index Profile for Broadband, Omnidirectional, and Polarization-Independent Antireflection

Black GaAs nanotip arrays (NTs) with 3300 nm lengths were fabricated via self-masked plasma etching. We show, both experimentally and numerically, that these NTs, with three gradient refractive index layers, effectively suppress Fresnel reflections at the air-GaAs interface over a broad range of wavelengths. These NTs exhibit exceptional UV-Vis light absorption (up to 99%) and maintain high NIR absorption (33-60%) compared to bare GaAs. Moreover, possessing a graded layer with a low refractive index (n = 1.01 to 1.12), they achieve angular and polarization-independent antireflection properties exceeding 80° at 632.8 nm, aligning with perfect antireflective coating theory predictions. This approach is anticipated to enhance the performance of optoelectronic devices across a wide range of applications.

Intelligent Packaging for Real-Time Monitoring of Food-Quality: Current and Future Developments

Food packaging encompasses the topical role of preserving food, hence, extending the shelf-life, while ensuring the highest quality and safety along the production chain as well as during storage. Intelligent food packaging further develops the functions of traditional packages by introducing the capability of continuously monitoring food quality during the whole chain to assess and reduce the insurgence of food-borne disease and food waste. To this purpose, several sensing systems based on different food quality indicators have been proposed in recent years, but commercial applications remain a challenge. This review provides a critical summary of responsive systems employed in the real-time monitoring of food quality and preservation state. First, food quality indicators are briefly presented, and subsequently, their exploitation to fabricate intelligent packaging based on responsive materials is discussed. Finally, current challenges and future trends are reviewed to highlight the importance of concentrating efforts on developing new functional solutions.

Fabrication and Characterization of Black GaAs Nanoarrays via ICP Etching

GaAs nanostructures have attracted more and more attention due to its excellent properties such as increasing photon absorption. The fabrication process on GaAs substrate was rarely reported, and most of the preparation processes are complex. Here, we report a black GaAs fabrication process using a simple inductively coupled plasma etching process, with no extra lithography process. The fabricated sample has a low reflectance value, close to zero. Besides, the black GaAs also displayed hydrophobic property, with a water contact angle of 125°. This kind of black GaAs etching process could be added to the fabrication workflow of photodetectors and solar cell devices to further improve their characteristics.

Editorial for the Special Issue on Micro- and Nano-Fabrication by Metal Assisted Chemical Etching

Discovered by Li and Bohn in 2000 [1], Metal Assisted Chemical Etching has been finally recognized as an emerging etching technology.[...].