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Layered Structured Materials and Nanotechnology for Photodetection
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
Felipe M. de Souza, Magdalene Asare, Ram K. Gupta
Photodetectors have become an increasingly important piece of technology that is used on communication devices, imaging, displays, and more sophisticated applications such as space observer telescopes. Based on that, photodetection consists of the conversion of specific light radiation into an electric signal. Such a process can take place through three sequential mechanisms which are harvesting of light, separation of excitons, and charge carrier transport to the desired electrodes. The equation that describes the light efficiency can be expressed by external quantum efficiency which is shown in Equation 16.1. Where Iph is defined as photocurrent which represents the variation among current under light and in the dark; Φ represents photon flux, which is the number of incident photons; qrepresents the unit of an electron charge; hν represents the energy of one photon, and P represents the power of the incident light [7].
Emerging Two-Dimensional Materials and Their Applications in Detection of Polarized Light
Published in Song Sun, Wei Tan, Su-Huai Wei, Emergent Micro- and Nanomaterials for Optical, Infrared, and Terahertz Applications, 2023
Xiao Luo, Qing Liu, Huidong Yin, Fucai Liu
The multi-degree of freedom of photodetection empowers a plethora of applications in modern society including optical imaging, communication and sensing as well as quantum physics, etc. In addition to the conventional detecting methods of intensity and wavelength, observations of the polarization and phase information of light attract many interests in recent years. From synthetic-, structural- and electronic-properties of materials, we discuss various experiment methods and physical mechanisms in detecting linear-polarization, circular-polarization of incident light based on emerging 2D material devices and nanophononics. Meanwhile, we also have given a comprehensive survey on the recent development of 2D material photodetectors based diverse nanostructures. Up to date, the wafer-scale growth of 2D materials has make a great progress, further improvement of the crystal quality will make the commercialization of 2D material device available soon. The design of novel van der Waals heterostructure and twist samples would provide more functional optoelectronic device of 2D materials. Due to the unique optoelectronic properties associated with 2D materials, we have witnessed great successes in improving the detection performance of degrees of freedom of light, and look forward to future developments in commercial applications.
Optical Sources and Detectors
Published in Z. Ghassemlooy, W. Popoola, S. Rajbhandari, Optical Wireless Communications, 2019
Z. Ghassemlooy, W. Popoola, S. Rajbhandari
Photodetection is the process of converting information-bearing optical radiation into its equivalent electrical signal with the aim of recovering the transmitted information. At the transmitter, the information can be encoded on the frequency, phase, or intensity of the radiation from an optical source. This encoded radiation is then transmitted to the Rx via the free space channel or the optical fibre. The Rx front-end devices (telescope and optical filter) focus the filtered radiation onto the PD surface in the focal plane. There are two possible detection schemes widely adopted in optical communications: intensity modulation-direct detection (IM-DD) and coherent schemes. IM-DD is the simplest and most widely used in OWC systems. Coherent detection schemes offer the potential of restoring full information on the optical carrier, namely the amplitude (in-phase (I) component) and phase (quadrature (Q) component) of the complex optical electric field and the state of polarisation of the signal. However, such Rxs are sensitive to the phase and the state of polarisation of the received optical signal. Table 2.7 depicts the comparison between IM-DD and coherent schemes [22].
Zinc sulfide based thin film photodetector prepared by spray pyrolysis
Published in Instrumentation Science & Technology, 2023
Natheer A. Algadri, Ahmad M. AL-Diabat, Naser M. Ahmed
Up to the present, there are many positive technical features of photodetector devices for convenient applications including low dark current, high-speed performance, simple fabrication, optoelectronic integration ease, low noise, and high speed performance. These characteristics help obtain an efficient and high performance photodetection, including computed tomography, chemical detection, medical imaging, and missile warning systems.[20] The mechanism of these devices is the response to light illumination illustrated through adsorption and desorption of O2 on its outer layer. Thus, the focus on this layer is exposed to light while fabricating the devices and this study pays attention to this point.[21,22]