We have developed equations taking into account both multiple-trapping and hopping processes for describing transport phenomena in disordered semiconductors. These equations have been introduced into a numerical simulation to model the steady state dark conductivity and photoconductivity as well as the modulated photoconductivity. The influence of parameters such as the density of states and attempt-to-hop frequency on the results of these experiments has been investigated. Steady state and modulated photoconductivity experiments have been performed on a hydrogenated amorphous silicon film in the temperature range 18-300 K and the results have been compared with those from the numerical simulation. This comparison shows that the latter provides a suitable interpretation of the experimental behaviours observed in both experiments.
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http://dx.doi.org/10.1088/0953-8984/21/4/045508 | DOI Listing |
Adv Sci (Weinh)
January 2025
Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, P. R. China.
In this manuscript, an all-optical modulation photodetector based on a CdS/graphene/Ge sandwich structure is designed. In the presence of the modulation (near-infrared) light, the Fermi level of the graphene channel shifts, allowing for the tuning of the visible light response speed as well as achieving a broad responsivity range from negative (-3376 A/W) to positive (3584 A/W) response. Based on this, logical operations are performed by adjusting the power of the modulation light superimposed with the signal light.
View Article and Find Full Text PDFNatl Sci Rev
January 2025
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
The intentional manipulation of carrier characteristics serves as a fundamental principle underlying various energy-related and optoelectronic semiconductor technologies. However, achieving switchable and reversible control of the polarity within a single material to design optimized devices remains a significant challenge. Herein, we successfully achieved dramatic reversible p-n switching during the semiconductor‒semiconductor phase transition in BiI via pressure, accompanied by a substantial improvement in their photoelectric properties.
View Article and Find Full Text PDFACS Omega
December 2024
School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, U.K.
Adv Mater
December 2024
State Key Laboratory of Silicon and Advanced Semiconductor Materials, Cyrus Tang Center for Sensor Materials and Applications, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310058, China.
2D-layered materials are recognized as up-and-coming candidates to overcome the intrinsic physical limitation of silicon-based devices. Herein, the coexistence of positive persistent photoconductivity (PPPC) and negative persistent photoconductivity (NPPC) in SnSe thin films prepared by pulsed laser deposition provides an excellent avenue for engineering novel devices. It is determined that surface oxygen is co-regulated by physisorption and chemisorption, and the NPPC is attributed to the photo-controllable oxygen desorption behavior.
View Article and Find Full Text PDFAdv Mater
December 2024
Department of Materials Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, P. R. China.
Optoelectronic devices with imaging and recognition capabilities are crucial for developing artificial visual system (AVS). Bias-switchable photodetection and photosynaptic devices have been developed using 2D perovskite oxide/organic heterojunctions. This unique structure allows for modulated carrier dynamics under varied bias conditions, enabling the devices to function as photodetectors without bias and as photosynapses with bias.
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