Effect of variation of thickness of TiO2 on the photovoltaic performance of n-TiO2/p-Si heterostructure

Dewasi, Avijit; Mitra, Anirban

doi:10.1007/s10854-017-7751-3

Cited by 17 publications

(5 citation statements)

References 23 publications

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“…On the other hand, electrons face hardly any barrier to surmount; hence, they drift easily from the TiO 2 side to the Si side, giving rise to photocurrent. Such heterojunctions with valence band offset values as large as 2.8 eV, facilitating electron-selective transport, can be used as highly efficient photodetectors …”

Section: Resultsmentioning

confidence: 99%

“…Such heterojunctions with valence band offset values as large as 2.8 eV, facilitating electron-selective transport, can be used as highly efficient photodetectors. 32 In light of the energy band diagram, we discuss the role of PMMA in improving photodetector performance. In our measurement, ΔE v does not show any significant change for STOPM compared to that of STO.…”

Section: Acs Appliedmentioning

confidence: 99%

“…This finally led to the development of various optoelectronic devices with useful applications in self-powering, rectification, enhanced on–off ratio, etc., in the spectral range of interest. − Among several material systems, the TiO 2 /Si heterojunction is being investigated because Si has already well-established technology. Furthermore, the large difference in Fermi levels between wide-bandgap TiO 2 and narrow-bandgap Si and the TiO 2 /Si heterojunction facilitate constructing multiband photodetectors. − Recently, some works demonstrated the formation of a hole–blocking interface between ultrathin TiO 2 film and crystalline silicon. , This carrier selection occurred due to a small conduction band offset (Δ E c ≈ 0.05 eV), which allows the passage of electrons through the TiO 2 layer, while a large valence-band offset (Δ E v ≈ 2.0 eV) blocks the holes …”

Section: Introductionmentioning

confidence: 99%

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PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

Pal,

Jana,

Kamparath

et al. 2024

ACS Appl. Nano Mater.

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This study reports on high-quality, crystalline, nanostructured TiO 2 thin films with large-area coverage prepared by the sol−gel process using PMMA (poly(methyl methacrylate)) as an additive for applications in visible-blind photodetection. The Si/TiO 2 p−n junction photodiodes, fabricated through an inexpensive yet simple process with the addition of PMMA, exhibit superior characteristics, making them excellent candidates for visible-blind photodetectors operational in the UV and NIR ranges. The addition of PMMA to the solution significantly enhances the crystalline and optical properties, as well as the nanostructure morphology of the TiO 2 films. It is demonstrated that the nanostructure morphology, refractive index, and bandgap of TiO 2 can be precisely tailored by controlling the TiO 2 sol/PMMA volume ratio. A valence band offset as large as 2.8 ± 0.20 eV is measured for the TiO 2 /Si heterointerface, ensuring hole blockage through the film and electron-selective transport. Application of the TiO 2 nanostructured thin films in the p-Si/n-TiO 2 junction photodiodes reveals an excellent rectification ratio of ∼2 × 10 4 with a leakage current as low as ∼10 −10 A and a superior phototo-dark current ratio of ∼8000 under 325 nm illumination. Under reverse bias conditions, the photodiodes exhibit a reasonably high photoresponsivity (>1 A/W) with a high detectivity of ∼1 × 10 13 Jones. Moreover, a response time of ∼200 ms is achieved using these photodiodes.

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Section: Resultsmentioning

confidence: 99%

Section: Acs Appliedmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

Pal,

Jana,

Kamparath

et al. 2024

ACS Appl. Nano Mater.

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“…The electrical parameters of the diode and the conduction mechanism are determined by analysing the I-V curves of the p-NiO/n-Si junction. According to the modified Shockley equation, the current characteristic of the p-n junction can be written as [45]:…”

Section: Resultsmentioning

confidence: 99%

Laser ablation fabrication of a p-NiO/n-Si heterojunction for broadband and self-powered UV–Visible–NIR photodetection

Chaoudhary

Dewasi

et al. 2022

Nanotechnology

Self Cite

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We report on the optoelectronic characteristics of p-NiO/n-Si heterojunction photodiodes for broadband photodetection, fabricated by depositing a p-type NiO thin film onto a commercial n-type silicon substrate using pulsed laser deposition (PLD) technique. The structural properties of the PLD-grown p-NiO material were analysed by means of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), confirming its crystalline nature and revealing the presence of Ni vacancies, respectively. Hall measurements confirmed the p-type semiconducting nature of the NiO thin film having a carrier concentration of 8.4 × 1016 cm-3. The current-voltage (I-V) characteristics of the p-NiO/n-Si heterojunction photodevice were investigated under different wavelengths ranging from UV to NIR. The self-bias properties under different illuminations of light were also explored systematically. Under self-bias condition, the photodiode exhibits excellent responsivities of 12.5 mA.W-1, 24.6 mA.W-1 and 30.8 mA.W-1 with illumination under 365 nm, 485 nm, and 850 nm light, respectively. In addition, the time dependency of the photoresponse of the fabricated photodevice has also been investigated and discussed thoroughly.

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“…TiO 2 is a material possessing a wide variety of qualities, including excellent chemical inertness, superior photocatalytic activity, good optical transmittance with a high refractive index in the visible range, and strong mechanical hardness. − It is widely used in photoconversion-related issues, e.g., photodetectors, photocatalysis, and resistive switching devices, as a passivation layer in solar cell devices, high-K gate dielectric for the transistors, etc. − …”

Section: Introductionmentioning

confidence: 99%

Reduced Work Function in Anatase ⟨101⟩ TiO₂ Films Self-Doped by O-Vacancy-Dependent Ti³⁺ Bonds Controlling the Photocatalytic Dye Degradation Performance

Das,

Shyam

2024

Langmuir

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TiO 2 has the proven capability of catalytically decomposing pollutants under light illumination, thereby embracing potential applications in wastewater management. The photocatalytic dye degradation activity is largely controlled by the optical band gap that dictates the extent of electron− hole pair generation via photon absorption, and the recombination kinetics of charges. In this context, the material's work function governs how easily the charge carriers can be transferred at the dye-adsorbed photocatalytically active sites. Accordingly, nanocrystalline TiO 2 thin films are grown in the anatase phase with ⟨101⟩ orientation, using RF magnetron sputtering at 200 °C. Besides studying the film's structural morphology, optical band gap, and elemental composition, the electronic properties are extensively investigated. The work function of the material was controlled by varying the O-vacancydependent Ti 3+ bonding configuration in the network. It has been demonstrated how the photocatalytic methylene blue dye degradation activity of the nanocrystalline TiO 2 films of predominantly the anatase phase improves on reducing the sputtering pressure during deposition. At a low deposition pressure of 20 mTorr, a low work function of ∼4.2 eV of the film, resulting from the formation of a Ti 3+ -bond through the O vacancies in the network, potentially increases its carrier lifetime and delivers the superior photocatalytic activity (∼82.7% dye degradation with a rate constant of k ∼ 0.0073 min −1 ) via silently facilitating fast electron transfer from the photocatalyst to the dye in the aqueous solution. The higher stoichiometric film prepared at p = 40 mTorr exhibits an inferior photocatalytic activity (∼20.4% dye degradation with a rate constant of k ∼ 0.0009 min −1 ), as retarded by its higher work function of ∼4.62 eV, despite retaining a relatively low band gap. Thus, without using any heterojunction or extrinsically doped photocatalyst, the dye degradation can be controlled simply by reducing the work function of nanocrystalline TiO 2 thin films via controlling the O-vacancy-dependent Ti 3+ bonding in its self-doped network.

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Effect of variation of thickness of TiO2 on the photovoltaic performance of n-TiO2/p-Si heterostructure

Cited by 17 publications

References 23 publications

PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

Laser ablation fabrication of a p-NiO/n-Si heterojunction for broadband and self-powered UV–Visible–NIR photodetection

Reduced Work Function in Anatase ⟨101⟩ TiO₂ Films Self-Doped by O-Vacancy-Dependent Ti³⁺ Bonds Controlling the Photocatalytic Dye Degradation Performance

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Effect of variation of thickness of TiO2 on the photovoltaic performance of n-TiO2/p-Si heterostructure

Cited by 17 publications

References 23 publications

PMMA as an Additive for Nanostructured TiO2 Thin Films for Heterojunction Visible-Blind Photodetectors

PMMA as an Additive for Nanostructured TiO2 Thin Films for Heterojunction Visible-Blind Photodetectors

Laser ablation fabrication of a p-NiO/n-Si heterojunction for broadband and self-powered UV–Visible–NIR photodetection

Reduced Work Function in Anatase ⟨101⟩ TiO2 Films Self-Doped by O-Vacancy-Dependent Ti3+ Bonds Controlling the Photocatalytic Dye Degradation Performance

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PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

PMMA as an Additive for Nanostructured TiO₂ Thin Films for Heterojunction Visible-Blind Photodetectors

Reduced Work Function in Anatase ⟨101⟩ TiO₂ Films Self-Doped by O-Vacancy-Dependent Ti³⁺ Bonds Controlling the Photocatalytic Dye Degradation Performance