Phys.org March 13, 2023 The materials used to make photodetectors often hamper efforts to make improved broadband nanoscale photodetectors. To overcome these difficuties a team of researchers in the US (San Francisco State University, Stanford University) developed a photodetector that has improved sensitivity in the ultraviolet to near-infrared light range. High photoresponsivity at wavelength 400 nm measured at 77 K, which translates into an external quantum efficiency. The 90% rise time of the devices at 77 K is 0.1 ms, suggesting they can operate at the speed of ≈10 kHz. High-performance broadband photodetector with spectral coverage ranging from 380 to 1000 nm was demonstrated. According to […]
Tag Archives: Photodetectors
Paper-supported photodetectors
Nanowerk January 5, 2023 An international team of researchers (Spain, Saudi Arabia, China) integrated semiconducting devices on cellulose paper substrate through a simple abrasion technique that yielded high-performance photodetectors. A solvent-free WS2 film deposited on paper favored an effective electron-hole separation and hampered recombination. The prototype photodetectors exhibited a sensitive photoresponse over a wide spectral range spanning from ultraviolet (365 nm) to near-infrared (940 nm). They found that ambient oxygen molecules decreased the photoresponse and stability of the photodetector. By controlling environmental exposure, they were able to increase the performance of the detector. They built a spectrometer using a paper-based […]
Photon-controlled diode: An optoelectronic device with a new signal processing behavior
Phys.org July 1, 2022 The photodetector is a key component in optoelectronic integrated circuits. Although there are various device structures and mechanisms, the output current changes either from rectified to fully-on or from fully-off to fully-on after illumination. According to researchers in China the device that changes the output current from fully-off to rectified should be possible. They designed a photon-controlled diode based on a n/n− molybdenum disulfide junction. Schottky junctions formed at the cathode and anode either prevent or allow the device to be rectifying, so that the output current of the device changes from fully-off to rectified. By […]
Soft semiconductors that stretch like human skin can detect ultra-low light levels
Science Daily December 15, 2021 An international team of researchers (USA – Georgia Institute of Technology, Chile) has demonstrated a new level of stretchability for a photodetector made from a synthetic polymer and an elastomer that absorbs light to produce an electrical current. It is up to 200% more stretchable than its original dimension without significantly losing its electric current. They found the right combination of chemical compounds to produce a super-soft material with the ability to generate and conduct electricity when exposed to light and the right ratio for all parts of the semiconductor layer to maintain high performance […]
Laying the groundwork for ultra-thin, energy efficient photodetector on Gorilla glass
Nanowerk November 2, 2020 Direct growth of high-performance, scalable, and reliable electronic materials on glass is difficult owing to low thermal budget. Researchers at the Pennsylvania State University have addressed the issue by relatively low-temperature (<600 °C) metal–organic chemical vapor deposition growth of atomically thin MoS2 on multicomponent glass and fabrication of low-power phototransistors using atomic layer deposition (ALD)-grown, high-k, and ultra-thin Al2O3 as the top-gate dielectric, circumventing the challenges associated with the ALD nucleation of oxides on inert basal planes of van der Waals materials. The MoS2 photodetectors demonstrate the ability to detect low-intensity visible light at high speed […]
Broad spectrum: Novel hybrid material proves an efficient photodetector
Phys.org April 9, 2020 The MOF compound developed by researchers in Germany comprises an organic material integrated with iron ions. The MOF forms superimposed layers with semiconducting properties, which makes it potentially interesting for optoelectronic applications. They found that the light sensitivity was dependent on temperature and wavelength from 400 to 1,575 nanometers. The spectrum of radiation goes from ultraviolet to near infrared. As the bandgap in the material is very small, only very little light energy is required to induce the electricity. The performance of the detector can be improved by cooling the detector down to lower temperatures and […]
Scientists create thin films with tantalizing electronic properties
Science Daily December 23, 2019 An international team of researchers (USA – SUNY New York, Los Alamos National Laboratory, Rensselaer Polytechnic Institute, China) has fabricated barium zirconium sulfide (BaZrS3) thin films by sulfurization of oxide films deposited by pulsed laser deposition. They showed that these films are n-type with carrier densities in the range of 1019-1020 cm−3. Temperature dependent conductivity measurements suggest shallow donor levels. By assuring that BaZrS3 is a promising candidate, these results potentially unleash a family of chalcogenide perovskites for optoelectronics such as photodetectors, photovoltaics, and light emitting diodes…read more. TECHNICAL ARTICLE
New photodetector could improve night vision, thermal sensing and medical imaging
Phys.org June 28, 2018 Researchers at UCLA laid strips of graphene over a silicon dioxide layer, which itself covers a base of silicon. Then, they created a series of comb-like nanoscale patterns, made of gold, with “teeth” about 100 nanometers wide. The graphene acts as a net to catch incoming photons and then convert them into an electrical signal. The gold comb-shaped nanopatterns transfer the information to a processor, which produces a corresponding high-quality image, even under low-light conditions. The design enables operation across a broad range of light, quicker processing of images and provides greater sensitivity to lower levels […]