Device Architecture for Visible and Near-Infrared Photodetectors Based on Two-Dimensional SnSe and MoS: A Review.

While band gap and absorption coefficients are intrinsic properties of a material and determine its spectral range, response time is mainly controlled by the architecture of the device and electron/hole mobility. Further, 2D-layered materials such as transition metal dichalogenides (TMDCs) possess inherent and intriguing properties such as a layer-dependent band gap and are envisaged as alternative materials to replace conventional silicon (Si) and indium gallium arsenide (InGaAs) infrared photodetectors. The most researched 2D material is graphene with a response time between 50 and 100 ps and a responsivity of <10 mA/W across all wavelengths.

Iron-Based Mixed Phosphate NaFe(PO)PO Thin Films for Sodium-Ion Microbatteries.

Iron-based polyanionic materials can be exploited to realize low cost, durable, and safe cathodes for both bulk and thin film sodium-ion batteries. Herein, we report pulsed laser deposited mixed phosphate NaFe(PO)PO as a positive electrode for thin film sodium-ion microbatteries. The bulk material and thin films of NaFe(PO)PO are employed by solution combustion synthesis (SCS) and the pulsed laser deposition (PLD) technique, respectively.

Low-cost VO(M1) thin films synthesized by ultrasonic nebulized spray pyrolysis of an aqueous combustion mixture for IR photodetection.

We report detailed structural, electrical transport and IR photoresponse properties of large area VO(M1) thin films deposited by a simple cost-effective two-step technique. Phase purity was confirmed by XRD and Raman spectroscopy studies. The high quality of the films was further established by a phase change from low temperature monoclinic phase to high temperature tetragonal rutile phase at 68 °C from temperature dependent Raman studies.

Toward a Fast and Highly Responsive SnSe-Based Photodiode by Exploiting the Mobility of the Counter Semiconductor.

In photodetection, the response time is mainly controlled by the device architecture and electron/hole mobility, while the absorption coefficient and the effective separation of the electrons/holes are the key parameters for high responsivity. Here, we report an approach toward the fast and highly responsive infrared photodetection using an n-type SnSe thin film on a p-Si(100) substrate keeping the overall performance of the device. The I- V characteristics of the device show a rectification ratio of ∼147 at ±5 V and enhanced optoelectronic properties under 1064 nm radiation.

Band Gap Engineering of Hexagonal SnSe Nanostructured Thin Films for Infra-Red Photodetection.

We, for the first time, provide the experimental demonstration on the band gap engineering of layered hexagonal SnSe nanostructured thin films by varying the thickness. For 50 nm thick film, the band gap is ~2.04 eV similar to that of monolayer, whereas the band gap is approximately ~1.