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Introduction to Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
In metals, the energy bands either overlap each other or a very small bandgap exists between the conduction and valence bands. This means that approximately all of the electrons lie in the conduction band and contribute to conduction. Semiconductors have a medium bandgap while insulators have a large bandgap. Popular semiconductors, such as germanium (Ge), silicon (Si), and gallium arsenide (GaAs) have bandgap values of 0.66, 1.1, and 1.42 eV (electron volts), respectively.
Application of Green Technology for Energy Conservation and Sustainable Development
Published in Miguel A. Esteso, Ana Cristina Faria Ribeiro, A. K. Haghi, Chemistry and Chemical Engineering for Sustainable Development, 2020
The third-generation solar cells are more efficient, safer, and cheaper to produce. Examples include perovskite solar cells based on hybrid perovskite structured crystals such as methylammonium lead iodide and other compound halides.12 These materials can be produced at lower temperatures and absorb light well. These are also cost-effective since they are made from commonly available industrial chemicals. Gallium arsenide is another material used to improve solar cell efficiency. Gallium arsenide solar panels are primarily used on spacecraft.
Photovoltaic Systems and Applications
Published in Radian Belu, Fundamentals and Source Characteristics of Renewable Energy Systems, 2019
Gallium Arsenide (GaAs) is a compound semiconductor made of gallium (Ga) and arsenic (As), having a crystal structure similar to that of silicon, and a high level of light absorptivity. To absorb the same amount of sunlight, GaAs requires only a layer of few micrometers thick while crystalline silicon requires a wafer of about 200–300 μm thick. GaAs has much higher energy conversion efficiency than crystal silicon, reaching about up to 30%. Having high resistance to heat it is the ideal choice for concentrator systems in which cell temperatures are higher. GaAs PV cells are also better for space applications where strong resistance to radiation damage and higher solar cell efficiency are required. The most important drawback of the GaAs PV cells is their higher cost of the single-crystal substrate on which the GaAs is grown on. Therefore GaAs materials are used in concentrator systems where only a small area of GaAs cells is needed.
Optimising standard solar cell designs for maximum efficiency using genetic algorithms
Published in International Journal of Modelling and Simulation, 2023
In terms of the GA, a significant advantage of this study was demonstrating the strong integration of 3D solar cell modelling with machine learning for a simulation software that has not previously been so tested. While the GA itself has the potential to be further automated, the cells modelled here demonstrate its capability in improving solar cell architectures, and there is significant potential to extend this to other, newer designs. The cells examined here are all silicon based; in further work, this process would be extended to include other common solar cell materials such as gallium arsenide. Overall, the GA was found to be a fast and accurate method of optimising solar cell designs in PC3D. The software complemented each other well, and efficiency improvements were achieved in each of the cell designs examined.
Experimental investigation of thin-film solar cells as a wearable power source
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Naresh Bangari, Vinod Kumar Singh, Virendra Kumar Sharma
Flexible thin-film solar system even though introduced in the year 1970s, but due to low efficiency, they are not much popular that of crystalline silicon solar system. Over the last decade, intensive research work had focused on semiconductor material synthesis and characterization by using nanotechnology (Ovshinsky and Izu 1985). Cadmium selenide thin-film solar cell characterizations such as optical, electrical, and applications are reported in Alamgir, Pervaiz, and Arif (2011). The design of nanostructure array of PN junction diode thin-film solar cells on transparent substrates is presented in Singh and Verma (2018). Gallium arsenide (GaAs) nanoparticle thin-film solar cell is shown the boost of current density by 31% as compared to bare thin-film GaAs solar cell (Guha, Kulman, and Tandem 1986).
Microbial toxicity of gallium- and indium-based oxide and arsenide nanoparticles
Published in Journal of Environmental Science and Health, Part A, 2020
Chi H. Nguyen, Jim A. Field, Reyes Sierra-Alvarez
The growing interest in the application of new III-V materials in semiconductor manufacturing has led to increasing concerns about possible toxic effects of CMP effluents generated during the planarization of thin films of III-V materials. In particular, there is a concern about the health risks and environmental impacts of As, which is well known as a carcinogenic and highly toxic metalloid.[21–23] The World Health Organization[24] and the U.S. Environmental Protection Agency[25] have established the maximum arsenic concentration allowed in drinking water at 10 μg L−1. Gallium arsenide has also been classified as an immune toxicant and a group I carcinogen to humans.[26] Less is known about the potential hazard and toxic effects of other soluble III-V species and III-V particulates.[20,27–30] This information gap, combined with the importance of CMP effluents, indicates the need for further research to characterize the ecotoxicity of III-V particles such as GaAs, InAs, Ga2O3, and In2O3. To the best of our knowledge, the acute toxicity of these materials toward microorganisms has not been reported to date. We are only aware of three recent studies that investigated the microbial toxicity of related nanomaterials, i.e., nano-sized gallium nitride [31] and nanoparticles of gallium(III) with different porphyrins.[32,33] Porphyrins are a group of heterocyclic macrocycle organic compounds that serve multiple purposes in many living organisms.[34]