Researchers design next-generation photodetector

EurekAlert  February 2, 2021 State-of-the-art LWIR detection technology still suffers from shortcomings such as low photocurrent gain and excess spectral noise. Researchers at Northwestern University used a new approach to design the photodetector using a type-II superlattice, a material system known for its outstanding growth uniformity and exceptional band structure engineering and applied the new material to a heterojunction phototransistor device structure. During testing each part of the photodetector was tuned to use the phototransistor to achieve high optical gain, low noise, and high detectivity. The material’s flexibility allowed for meticulous quantum mechanics-based band structure engineering for the heterostructure design, […]

The world’s first photodetector that can see all shades of light

Nanowerk  September 22, 2020 Atomically thin materials face an ongoing challenge of scalability, hampering practical deployment despite their fascinating properties. Although tin monosulfide (SnS) displays properties of superior carrier mobility and large absorption coefficient at atomic thicknesses, the lack of successful synthesis techniques to prepare large‐area and stoichiometric atomically thin SnS layers has prevented exploration of these properties for versatile applications. Researchers in Australia printed SnS layers with thicknesses varying from a single unit cell (0.8 nm) to multiple stacked unit cells (≈1.8 nm) synthesized from metallic liquid tin, with lateral dimensions on the millimeter scale. They exhibit a broadband […]

Black silicon photodetector breaks the 100% efficiency limit

Phys.org  August 14, 2020 Ultraviolet sensors are utilized in numerous fields although their performance is surprisingly poor. An international team of researchers (Finland, Spain, Germany) used a nanostructured silicon photodiode with self-induced junction to demonstrate that it is possible to make a device with a certified external quantum efficiency above 130% in UV range without external amplification. They showed that the high efficiency is based on effective utilization of multiple carrier generation by impact ionization taking place in the nanostructures. While the results can readily have a significant impact on the UV-sensor industry, the underlying technological concept can be applied […]