Effect of quantum confinement in CdSe/Se multilayer thin films prepared by PVD technique

Jesuraj, S. Anandh; Devadason, Suganthi; Kumar, M. Melvin David

doi:10.1016/j.mssp.2017.03.019

Cited by 19 publications

(4 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As it can be seen from this figure, the results obtained for Se films are characterized with transmission greater than 55 % for wavelength values greater than 500 nm. Similar results were obtained by Harpreet Singh [23] for Se films, Jassim, Zumaila, and Waly [27] for CdS thin films and Anandh et al [35] for CdSe films. It is observed that all the films are highly transparent, and the maximum transmittance is about 75 %.…”

Section: Figure 2 Plot Of Transmittance (T %) Versus Wave-length (λ) Of Incident Photon At Different Se Films Thicknesses (T)*supporting

confidence: 85%

“…X-ray diffraction data of selenium films well agrees with that of trigonal selenium peaks [JCPDS: 0362] [15], [17]. The XRD result showed that the selenium film is amorphous in nature due to this arrangement of atoms in thin films [35].…”

Section: Results and Discussion Sectionmentioning

confidence: 55%

“…The energy band gap of films varied in the range (2.0 to 2.3) eV [37]. The value of the optical band gap energy is found to be decreasing from (2.3 to 2.0 eV) [35] as the film thickness increases from (200 to 1000 nm), which shows its capabilities to be used as an absorber layer in photovoltaic applications and wide band gap materials (Cdo), suitable for solar cells [38].…”

Section: Figure 2 Plot Of Transmittance (T %) Versus Wave-length (λ) Of Incident Photon At Different Se Films Thicknesses (T)*mentioning

confidence: 94%

See 2 more Smart Citations

Impact of Thickness on the Optical Properties of Selenium Thin Films

Udachan¹,

Ayachit²,

Udachan

et al. 2021

IyU

View full text Add to dashboard Cite

Objectives: The primary objective of this investigation is to make a systematic study on the impact of thickness on optical properties, such as energy gap, absorption coefficient, optical density etc., for selenium thin films. Understanding of the band gap energy and its influence on film thickness is of utmost importance in acquiring the intended electrical characterization of semiconducting films. Materials and methods: Ultra-purity selenium (99.99 %) was deposited on glass substrates. During deposition, the glass substrate with its holder were rotated with constant speed to have a smooth coating. Results and discussions: The XRD findings indicate that selenium is amorphous in nature. The optical band gap energy is found to be decreasing form (2.3 to 2eV) with the rise of film thickness in interval (200 to 1000 nm). The band gap energy obeys inverse square law with respect to thickness. Conclusion: We have properly grown thin films of Se below the De Broglie wavelength limit by thermal evaporation in vacuum. The optical density varies directly with film thickness. The absorption coefficients were in the interval (0.5 to 4) × 107m-1. The AFM results confirmed that the Se nano-size increases with the increase in thickness. Both the grain boundaries and sub-grain regions are clearly visible in the SEM micrographs

show abstract

Section: Figure 2 Plot Of Transmittance (T %) Versus Wave-length (λ) Of Incident Photon At Different Se Films Thicknesses (T)*supporting

confidence: 85%

Section: Results and Discussion Sectionmentioning

confidence: 55%

Section: Figure 2 Plot Of Transmittance (T %) Versus Wave-length (λ) Of Incident Photon At Different Se Films Thicknesses (T)*mentioning

confidence: 94%

See 1 more Smart Citation

Impact of Thickness on the Optical Properties of Selenium Thin Films

Udachan¹,

Ayachit²,

Udachan

et al. 2021

IyU

View full text Add to dashboard Cite

show abstract

“…Applying the quantum confinement effect, the bandgap energy of the TiN films made using 150 to 750 laser pulses was fitted to the following equation: − E normalg = E normalg , bulk + B / t 2 , where E g ,bulk is the band gap energy of the bulk TiN crystal, B is the quantum confinement constant, and t is the thickness of the TiN films. As seen in Figure , the bandgap energy data fits well with eq with the goodness of the fitting ( R 2 ) value close to unity (0.99) and a low reduced chi-square (χ 2 ) value was 3.6 × 10 –4 .…”

Section: Resultsmentioning

confidence: 99%

Modulation of Structural, Electronic, and Optical Properties of Titanium Nitride Thin Films by Regulated In Situ Oxidation

Roy

Sarkar

Som

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Epitaxial titanium nitride (TiN) and titanium oxynitride (TiON) thin films have been grown on sapphire substrates using a pulsed laser deposition (PLD) method in high-vacuum conditions (base pressure <3 × 10 −6 T). This vacuum contains enough residual oxygen to allow a time-independent gas phase oxidation of the ablated species as well as a time-dependent regulated surface oxidation of TiN to TiON films. The time-dependent surface oxidation is controlled by means of film deposition time that, in turn, is controlled by changing the number of laser pulses impinging on the polycrystalline TiN target at a constant repetition rate. By changing the number of laser pulses from 150 to 5000, unoxidized (or negligibly oxidized) and oxidized TiN films have been obtained with the thickness in the range of four unit cells to 70 unit cells of TiN/TiON. X-ray photoelectron spectroscopy (XPS) investigations reveal higher oxygen content in TiON films prepared with a larger number of laser pulses. The oxidation of TiN films is achieved by precisely controlling the time of deposition, which affects the surface diffusion of oxygen to the TiN film lattice. The lattice constants of the TiON films obtained by x-ray diffraction (XRD) increase with the oxygen content in the film, as predicted by molecular dynamics (MD) simulations. The lattice constant increase is explained based on a larger electrostatic repulsive force due to unbalanced local charges in the vicinity of Ti vacancies and substitutional O. The bandgap of TiN and TiON films, measured using UV−visible spectroscopy, has an asymmetric V-shaped variation as a function of the number of pulses. The bandgap variation following the lower number of laser pulses (150−750) of the V-shaped curve is explained using the quantum confinement effect, while the bandgap variation following the higher number of laser pulses (1000−5000) is associated with the modification in the band structure due to hybridization of O 2p and N 2p energy levels.

show abstract