“…[1][2][3] Titanium dioxide (TiO 2 ), with an appropriate bandgap (3.0-3.2 eV), [4] high carrier mobility (≈39 cm 2 V −1 s −1 ), [5] and non-toxicity, has been considered as an ideal active material for UV-A PD applications. [6,7] Meanwhile, the construction of ultrahigh-performance photodetectors based on a 1D structure with Schottky junction has attracted much attention. [8][9][10][11] The problem of charge recombination due to the lattice mismatch between the n-layer and p-layer is overcome, however, the high state density at the TiO 2 surface will cause nonradiative charge recombination.…”
Two-dimensional transition metal carbides and nitrides (MXenes) show tremendous potential for optoelectronic devices due to their excellent electronic properties. Here, a high-performance ultraviolet photodetector based on TiO 2 nanorod arrays/Ti 3 C 2 T x MXene van der Waals (vdW) Schottky junction by allsolution process technique is reported. The Ti 3 C 2 T x MXene modulated by the Au electrode increases its work function from 4.41 to 5.14 eV to form a hole transport layer. Complemented by the dangling bond-free surface of Ti 3 C 2 T x , the Fermi-level pinning effect is suppressed and the electric-field strength of the Schottky junction is enhanced, which promotes charge separation and transport. After applying a bias of −1.5 V, the photovoltaic effect is favorably reinforced, while the hole-trapping mechanism (between TiO 2 and oxygen) and reverse pyroelectric effect are largely eliminated. As a result, the responsivity and specific detectivity of the device with FTO/TiO 2 nanorod arrays/ Ti 3 C 2 T x /Au structure reach 1.95 × 10 5 mA W −1 and 4.3 × 10 13 cm Hz 1/2 W −1 (370 nm, 65 mW cm −2 ), respectively. This work provides an effective approach to enhance the performance of photodetectors by forming the vdW Schottky junction and choosing metal electrodes to modulate MXene as a suitable charge transport layer.
“…[1][2][3] Titanium dioxide (TiO 2 ), with an appropriate bandgap (3.0-3.2 eV), [4] high carrier mobility (≈39 cm 2 V −1 s −1 ), [5] and non-toxicity, has been considered as an ideal active material for UV-A PD applications. [6,7] Meanwhile, the construction of ultrahigh-performance photodetectors based on a 1D structure with Schottky junction has attracted much attention. [8][9][10][11] The problem of charge recombination due to the lattice mismatch between the n-layer and p-layer is overcome, however, the high state density at the TiO 2 surface will cause nonradiative charge recombination.…”
Two-dimensional transition metal carbides and nitrides (MXenes) show tremendous potential for optoelectronic devices due to their excellent electronic properties. Here, a high-performance ultraviolet photodetector based on TiO 2 nanorod arrays/Ti 3 C 2 T x MXene van der Waals (vdW) Schottky junction by allsolution process technique is reported. The Ti 3 C 2 T x MXene modulated by the Au electrode increases its work function from 4.41 to 5.14 eV to form a hole transport layer. Complemented by the dangling bond-free surface of Ti 3 C 2 T x , the Fermi-level pinning effect is suppressed and the electric-field strength of the Schottky junction is enhanced, which promotes charge separation and transport. After applying a bias of −1.5 V, the photovoltaic effect is favorably reinforced, while the hole-trapping mechanism (between TiO 2 and oxygen) and reverse pyroelectric effect are largely eliminated. As a result, the responsivity and specific detectivity of the device with FTO/TiO 2 nanorod arrays/ Ti 3 C 2 T x /Au structure reach 1.95 × 10 5 mA W −1 and 4.3 × 10 13 cm Hz 1/2 W −1 (370 nm, 65 mW cm −2 ), respectively. This work provides an effective approach to enhance the performance of photodetectors by forming the vdW Schottky junction and choosing metal electrodes to modulate MXene as a suitable charge transport layer.
“…The binding energy at 685 eV and 498 eV at in the XPS survey spectrum (Fig. 3 a) indicates the F 1 s peak and Sn3 d that may be appeared because the XPS testing was performed on samples mounted on the FTO glass [ 35 , 36 ]. Figure 3 b shows that there are three peaks in the C1 s spectra of PEDOS, which is contributed to the signal peaks of C–C, C–Se and C–O bonds.…”
Section: Resultsmentioning
confidence: 99%
“…Under UV light, ZnO NRs produce a lot of electron-pore pairs. Meanwhile, the O 2− ions of ZnO NRs combine with the charged holes to arose a O 2 gas, forming free electrons as the main charge carrier under the external bias [ 35 , 36 ]. Fig.…”
In this work, we successfully assembled an organic–inorganic core–shell hybrid p-n heterojunction ultraviolet photodetector by the electropolymerization deposition of poly(3,4-ethylenedioxyselenophene) (PEDOS) on the surface of zinc oxide nanoarrays (ZnO NRs). The structures of composite were confirmed by FTIR, UV–Vis, XRD and XPS. Mott–Schottky analysis was used to study the p-n heterojunction structure. The photodetection properties of ZnO NRs/PEDOS heterojunction ultraviolet photodetector were systematically investigated current–voltage (I–V) and current–time (I–t) analysis under different bias voltages. The results showed that PEDOS films uniformly grew on ZnO NRs surface and core–shell structure was formed. The p-n heterojunction structure was formed with strong built-in electric field between ZnO NRs and PEDOS. Under the irradiation of UV light, the device showed a good rectification behavior. The responsivity, detection rate and the external quantum efficiency of the ultraviolet photodetector reached to 247.7 A/W, 3.41 × 1012 Jones and 84,000% at 2 V bias, respectively. The rise time (τr) and fall time (τf) of ZnO NRs/PEDOS UV photodetector were obviously shortened compared to ZnO UV photodetector. The results show that the introduction of PEDOS effectively improves the performance of the UV photodetector.
“…TiO 2 is one of the most usable oxides in industrial applications and in various fields such as photovoltaic [1], photocatalytic degradation of organic wastes [2][3][4][5][6], self-cleaning [7], gas sensing [8], ultra-violet (UV) photodetecting [9], hydrogen generation [10,11], etc. The photocatalytic property of TiO 2 coatings is the most common and widely used in industry because of their high efficiency in degradation of organic pollutants upon UV illumination [12][13][14].…”
TiO2 thin films on polymethyl methacrylate (PMMA) substrates were prepared on Al foils
using reactive dc magnetron sputtering followed by transformation to the PMMA substrates
via chemical method. The films were prepared at different temperature preparation routes of
100, 150 and 200C. XRD revealed the formation amorphous structure for films prepared at
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