Semiconductor Heterojunctions ☆

Skromme, Brian; Sujan, G.K.

doi:10.1016/b978-0-12-803581-8.11219-6

Cited by 12 publications

(6 citation statements)

References 49 publications

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“…Because of the band alignment and potential difference between the band positions, the photogenerated electrons follow the heterojunction mechanism, where the electrons present in the CB of CdS NRs layer are transferred to the CB of CdSe QDs layer and to the Ag electrode. At the same time, holes in the VB of CdSe QDs are transferred to VB of CdS NRs and to the ITO (figure 5(a)) [51]. On the other hand, in device B, charge excitons are generated in the CdSe QDs: graphene nanocomposite under light illumination and charge carrier separation is occurred under applied electric field, however, in presence of graphene, charge carrier separation is enhanced due to nano heterojunction formation at the interface of CdSe induces the charge carrier transportation effectively.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics

et al. 2021

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Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs in a single hand to realize the high-performance optoelectronic devices. In the present study, high-performance photodetector based on graphene: CdSe QDs/CdS nanorod heterostructures, are demonstrated. The resulting heterojunction photodetector with device configuration ITO/graphene: CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW -1 and specific detectivity of 6.85×10 12 Jones measured at 530 nm. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector was explored. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated. Also, the graphene: CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilization of advantageous features of graphene in optoelectronic devices.

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Section: Resultsmentioning

confidence: 99%

Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics

et al. 2021

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“…p-type semiconductor indicates that their lower valence electron in the semiconductor. The combination of two semiconductors (p-type and n-type) is labeled as a heterojunction [170]. Heterojunctions could also be formed from the same type such as CuWO 4 /WO 3 , where both films showed n-type properties below visible light irradiation [171].…”

Section: Heterojunction Formation Of Womentioning

confidence: 99%

Recent advancements in strategies to improve performance of tungsten-based semiconductors for photocatalytic hydrogen production: a review

Mim¹,

Aldeen²,

Alhebshi³

et al. 2021

J. Phys. D: Appl. Phys.

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Multiple efforts have been made to find and utilize sustainable renewable energy to replace fossil fuels that have polluted the environment. Among many semiconductors, tungsten trioxide (WO3) is a promising semiconductor due to its narrow band gap (between 2.5 and 3 eV) and has stable chemical and physical properties. WO3 can absorb a broad range of the solar light spectrum but it is unable to produce hydrogen from water due to its lower conduction band position. However, the high oxidation power of the valence band; nontoxicity and resiliency towards harsh environments such as continuous contact to water and solar irradiation makes it a very promising photocatalyst. The current review article is a literature review on the basis of keywords including hydrogen production; tungsten-based semiconductors; heterojunction formation; band gap engineering, thermodynamics and visible light active photocatalysts. This review aims to summarize the current progress in WO3 based materials for photocatalytic H2 production along with the recent strategies employed for modifications of WO3 based materials for efficient photoactivity. Conventionally, the fundamentals along with the thermodynamics for photocatalytic hydrogen production based on heterogeneous photocatalysts have been discovered. The structural modifications of WO3 with band gap engineering for efficiency enhancement are systematically presented. Recent approaches such as coupling of semiconductors, band gap engineering, establishment of heterojunctions, Z-scheme and step-scheme development to improve the surface sensitization of a semiconductor have been thoroughly discussed. Co-doping semiconductors have proven to reduce the band gap notably and their outstanding electronic band position for visible light photocatalysis has been identified. Modification, doping or coupling of WO3 with a cocatalyst is necessary to change the band gap position. This review article summarizes progress of modifications of WO3 and discusses the future research direction for designing the most efficient WO3 composite towards hydrogen production.

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“…Semiconductor materials can be used for water splitting if the lowest level of the conduction band (CB) is more negative than the H + /H 2 reduction potential (0 V vs. the normal hydrogen electrode (NHE)), and the highest level of valence band is more positive than the H 2 O/O 2 oxidation potential (1.23 V vs. NHE). [ 8 ] Combinations of n-type metal oxides and p-type transition metal dichalcogenides (TMDs) result in a semiconductor n-p heterojunction which can absorb a wide spectrum of solar energy containing both UV and visible light [ 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

MoS2@ZnO Nanoheterostructures Prepared by Electrospark Erosion for Photocatalytic Applications

Potgieter

Usoltseva

et al. 2021

Nanomaterials

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MoS2@ZnO nanoheterostructures were synthesized by electrospark erosion of zinc granules in a hydrogen peroxide solution and simultaneous addition of MoS2 nanostructured powder into the reaction zone. The morphology, size of the crystallites, as well as elemental and phase composition of the prepared structures, were examined using transmission electron microscopy and X-ray diffraction analysis. It was found that the synthesized products represent heterostructures containing MoS2 nanoparticles formed on ZnO nanoparticles. Raman spectroscopy and photoluminescence analysis were also used for characterization of the prepared heterostructures. The obtained MoS2@ZnO nanostructures revealed an intense broad emission band ranging from 425 to 625 nm for samples with different fractions of MoS2. Photocatalytic measurements showed that the maximal hydrogen evolution rate of the prepared nanoheterostructures was about 906.6 μmol·g−1·h−1. The potential of their application in photocatalytic water splitting was also estimated.

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Semiconductor Heterojunctions ☆

Cited by 12 publications

References 49 publications

Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics

Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics

Recent advancements in strategies to improve performance of tungsten-based semiconductors for photocatalytic hydrogen production: a review

MoS2@ZnO Nanoheterostructures Prepared by Electrospark Erosion for Photocatalytic Applications

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