Author Correction: Solution-processed hybrid perovskite photodetectors with high detectivity.

This Article contains an error in Equation 2 in that the denominator is inverted. This has not been fixed in the PDF or HTML versions of the Article but can be seen in the associated Correction

High-performance near-infrared photodetector based on nano-layered MoSe2

In recent years, the integration of two-dimensional (2D) nanomaterials, especially transition metal chalcogendies (TMCs) and dichalcogendies (TMDCs), into electronic devices have been extensively studied owing to their exceptional physical properties such as high transparency, strong photoluminescence, and tunable bandgap depending on the number of layers. Herein, we report the optoelectronic properties of few-layered MoSe2-based backgated phototransistor used for photodetection. The photoresponsivity could be easily controlled to reach a maximum value of 238 AW–1 under near-infrared light excitation, achieving a high specific detectivity D∗ = 7.6×10** cmHz*/1W3* . Few-layered MoSe2 exhibited excellent optoelectronic properties as compared with those reported previously for multilayered 2D material-based photodetectors, indicating that our device is one of the best high-performance nanoscale near-infrared photodetector based multilayered two-dimensional materials

Ambipolar Solution-processed Hybrid Perovskite Phototransistors

Organolead halide perovskites have attracted substantial attention due to their excellent physical properties, which enable them to serve as the active material in emerging hybrid solid-state solar cells. Here we investigate the phototransistors based on hybrid perovskite films, and provide direct evidence for their superior carrier transport property with ambipolar characteristics. The field-effect mobilities for triiodide perovskites at room temperature are measured as 0.18 (0.17) cm2 V-1 s-1 for holes (electrons), which increase to 1.24 (1.01) cm2 V-1 s-1 for mixed halide perovskites. The photoresponsivity of our hybrid perovskite devices reaches 320 A W-1, which is among the largest values reported for phototransistors. Importantly, the phototransistors exhibit an ultrafast photoresponse speed of less than 10 {\mu}s. The solution-based process and excellent device performance strongly underscore hybrid perovskites as promising material candidates for photoelectronic applications

Self-Powered, Highly Sensitive, High Speed Photodetection Using ITO/WSe2/SnSe2 Vertical Heterojunction

Two dimensional transition metal di-chalcogenides (TMDCs) are promising candidates for ultra-low intensity photodetection. However, the performance of these photodetectors is usually limited by ambience induced rapid performance degradation and long lived charge trapping induced slow response with a large persistent photocurrent when the light source is switched off. Here we demonstrate an indium tin oxide (ITO)/WSe$_2$/SnSe$_2$ based vertical double heterojunction photoconductive device where the photo-excited hole is confined in the double barrier quantum well, whereas the photo-excited electron can be transferred to either the ITO or the SnSe$_2$ layer in a controlled manner. The intrinsically short transit time of the photoelectrons in the vertical double heterojunction helps us to achieve high responsivity in excess of $1100$ A/W and fast transient response time on the order of $10$ $\mu$s. A large built-in field in the WSe$_2$ sandwich layer results in photodetection at zero external bias allowing a self-powered operation mode. The encapsulation from top and bottom protects the photo-active WSe$_2$ layer from ambience induced detrimental effects and substrate induced trapping effects helping us to achieve repeatable characteristics over many cycles

Use of both linear and logarithmic transfer functions to increase dynamic range of visual channel

Using both linear and logarithmic transfer functions in the visual channels of a dual channel radiometer increases the dynamic range to better than 1 to 10,000 foot-lamberts

Improved detectivity of pyroelectric detectors

High detectivity single-element SBN pyroelectric detectors were fabricated. The theory and technology developments related to improved detector performance were identified and formulated. Improved methods of material characterization, thinning, mounting, blackening and amplifier matching are discussed. Detectors with detectivities of 1.3 x 10 to the 9th power square root of Hz/watt at 1 Hz are reported. Factors limiting performance and recommendations for future work are discussed

Monolayer MoS2/GaAs heterostructure self-driven photodetector with extremely high detectivity

Two dimensional material/semiconductor heterostructures offer alternative platforms for optoelectronic devices other than conventional Schottky and p-n junction devices. Herein, we use MoS2/GaAs heterojunction as a self-driven photodetector with wide response band width from ultraviolet to visible light, which exhibits high sensitivity to the incident light of 635 nm with responsivity as 446 mA/W and detectivity as 5.9*10^13 Jones (Jones = cm Hz1/2 W-1), respectively. Employing interface design by inserting h-BN and photo-induced doping by covering Si quantum dots on the device, the responsivity is increased to 419 mA/W for incident light of 635 nm. Distinctly, attributing to the low dark current of the MoS2/h-BN/GaAs sandwich structure based on the self-driven operation condition, the detectivity shows extremely high value of 1.9*10^14 Jones for incident light of 635 nm, which is higher than all the reported values of the MoS2 based photodetectors. Further investigations reveal that the MoS2/GaAs based photodetectors have response speed with the typical rise/fall time as 17/31 {\mu}s. The photodetectors are stable while sealed with polymethyl methacrylate after storage in air for one month. These results imply that monolayer MoS2/GaAs heterojunction may have great potential for practical applications as high performance self-driven photodetectors

Photo-FETs: phototransistors enabled by 2D and 0D nanomaterials

The large diversity of applications in our daily lives that rely on photodetection technology requires photodetectors with distinct properties. The choice of an adequate photodetecting system depends on its application, where aspects such as spectral selectivity, speed, and sensitivity play a critical role. High-sensitivity photodetection covering a large spectral range from the UV to IR is dominated by photodiodes. To overcome existing limitations in sensitivity and cost of state-of-the-art systems, new device architectures and material systems are needed with low-cost fabrication and high performance. Low-dimensional nanomaterials (0D, 1D, 2D) are promising candidates with many unique electrical and optical properties and additional functionalities such as flexibility and transparency. In this Perspective, the physical mechanism of photo-FETs (field-effect transistors) is described and recent advances in the field of low-dimensional photo-FETs and hybrids thereof are discussed. Several requirements for the channel material are addressed in view of the photon absorption and carrier transport process, and a fundamental trade-off between them is pointed out for single-material-based devices. We further clarify how hybrid devices, consisting of an ultrathin channel sensitized with strongly absorbing semiconductors, can circumvent these limitations and lead to a new generation of highly sensitive photodetectors. Recent advances in the development of sensitized low-dimensional photo-FETs are discussed, and several promising future directions for their application in high-sensitivity photodetection are proposed.Peer ReviewedPostprint (author's final draft

PVF pyroelectric radiometer

Polyvinylfluoride (PVF) plastic film was found to be a good pyroelectric material. Radiometers using PVF were developed that exhibit high sensitivity and frequency response. Normalized detectivities of greater than 10 to the 8th power cm/Hz/w and responsivities on the order of 100,000 V/W were measured (500 C BB source, 0.1 Hz chopping frequency and 1 Hz bandwidth.