Structural and optical properties of CdTe/CdSe heterostructure multilayer thin films prepared by physical vapor deposition technique

Kumar, M. Melvin David; Devadason, Suganthi

doi:10.1007/s13204-012-0150-4

Cited by 33 publications

(8 citation statements)

References 30 publications

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“…, the electron–hole pair is forced closer together than its preferred distance). ,, Size tuning of QD PL is thus based on changing the magnitude of quantum confinement. The range of this tuning is determined by the bulk band gap energy (2.4, 1.8, and 1.5 eV for CdS, CdSe, and CdTe, respectively) ,, and the exciton Bohr radius (∼3, ∼5, and ∼7 nm, respectively), ,, both of which are set by the nanocrystal material.…”

Section: Catalog Of Materialsmentioning

confidence: 99%

Photoluminescent Nanoparticles for Chemical and Biological Analysis and Imaging

et al. 2021

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Research related to the development and application of luminescent nanoparticles (LNPs) for chemical and biological analysis and imaging is flourishing. Novel materials and new applications continue to be reported after two decades of research. This review provides a comprehensive and heuristic overview of this field. It is targeted to both newcomers and experts who are interested in a critical assessment of LNP materials, their properties, strengths and weaknesses, and prospective applications. Numerous LNP materials are cataloged by fundamental descriptions of their chemical identities and physical morphology, quantitative photoluminescence (PL) properties, PL mechanisms, and surface chemistry. These materials include various semiconductor quantum dots, carbon nanotubes, graphene derivatives, carbon dots, nanodiamonds, luminescent metal nanoclusters, lanthanidedoped upconversion nanoparticles and downshifting nanoparticles, triplet−triplet annihilation nanoparticles, persistent-luminescence nanoparticles, conjugated polymer nanoparticles and semiconducting polymer dots, multi-nanoparticle assemblies, and doped and labeled nanoparticles, including but not limited to those based on polymers and silica. As an exercise in the critical assessment of LNP properties, these materials are ranked by several application-related functional criteria. Additional sections highlight recent examples of advances in chemical and biological analysis, point-of-care diagnostics, and cellular, tissue, and in vivo imaging and theranostics. These examples are drawn from the recent literature and organized by both LNP material and the particular properties that are leveraged to an advantage. Finally, a perspective on what comes next for the field is offered.

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Section: Catalog Of Materialsmentioning

confidence: 99%

Photoluminescent Nanoparticles for Chemical and Biological Analysis and Imaging

et al. 2021

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“…2 Additionally, CdTe and CdSe are used in various other devices, such as thin film transistors, solar cell-based devices, photoconductors, gas sensors, acousto-optical devices and photographic photoreceptors, 3 and also in antibacterial applications. 4 CdSe and CdTe can be deposited by different techniques, namely spray pyrolysis, 1 thermal evaporation, 3,5,6 chemical bath deposition, 7 radio frequency sputtering 8 and dip coating. 9 Yadav et al 1 and Cristian et al 3 deposited CdSe using spray pyrolysis and thermal evaporation and studied the influence of the preparation condition on the structural and optical properties of the CdSe films.…”

Section: Introductionmentioning

confidence: 99%

Studies on cadmium telluride–cadmium selenide bilayer

ShreeBalakrishnan¹,

PriyaSubramanian²,

RanjaniPerchamy³

et al. 2015

Nanomaterials and Energy

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Group II-VI elements of the periodic table are suitable for electronic and optoelectronic applications. Cadmium selenide (CdSe) and cadmium telluride (CdTe) bilayer films were deposited onto well-cleaned glass substrates using vacuum evaporation technique. These films were analyzed using X-ray diffraction, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX) and UV-visible spectrophotometry to study their microstructural, morphological and optical properties. Crystallinity of CdSe film increased with increase in film thickness, which in turn favored the crystallinity of the CdTe layer deposited over CdSe. The CdTe/CdSe bilayer showed globular surface morphology, and the grain size of the films measured by FE-SEM micrographs range from 16 to 31 nm. EDAX analysis confirmed the presence of cadmium (Cd), selenium (Se) and tellurium (Te). Two electronic transitions were observed in the optical band gap of the CdTe/CdSe bilayer whose energy levels lie in between the energy band gap of the bulk CdTe and CdSe semiconductors. These electronic transitions are mainly due to the spin orbit split of valence band energy levels. IntroductionEco-friendly electricity-generation techniques, such as solar, geothermal and wind energy, are being used increasingly due to depleting levels of fossil fuels and environmental crises. Solar energy is the main source of eco-friendly electricity and has been used for several decades. Solar cells utilize bulk silicon (Si), and the production cost of Si is high. Hybrid solar cells utilize cadmium (Cd)-based binary compounds such as cadmium selenide (CdSe) and cadmium telluride (CdTe) due to their high absorption coefficients which envelop wider range of visible spectrum compared to Si solar cells. CdSe and CdTe are highly photosensitive and direct optical band gap materials (1·74 and 1·45 eV, respectively), which render them promising for usage in photovoltaic devices.1 Beside these applications, CdSe and CdTe have also gained importance in optoelectronic applications over recent decades. CdSe and CdTe are being used as the window and absorber layer, respectively, in photovoltaic devices.2 Additionally, CdTe and CdSe are used in various other devices, such as thin film transistors, solar cell-based devices, photoconductors, gas sensors, acousto-optical devices and photographic photoreceptors, 3 and also in antibacterial applications. Yadav et al. 1 and Cristian et al. 3 deposited CdSe using spray pyrolysis and thermal evaporation and studied the influence of the preparation condition on the structural and optical properties of the CdSe films. They also showed that the resistivity of the films exhibited semiconductor behavior and the band gap ranges from 1·65 to 1·75 eV for increasing substrate temperature and the speed of substrate rotation during deposition. Melvin David Kumar and Suganthi 5 prepared a CdTe/CdSe multilayer using the thermal evaporation technique and studied its structural and electrical properties. Dutta and Saikia 6 deposited a CdS, C...

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“…This can be done via a core-shell particle approach [26,27] or successive layer thin film deposition [28,29]. Examples of mixed element core and shell structures include CdS-ZnS [30], CdS-HgS [31], CdSe-CdS [32] and CdS-Ag 2 S [33].…”

Section: Introductionmentioning

confidence: 99%