Application of Nanostructured TiO₂ in UV Photodetectors: A Review

Abstract

moderate UV light is beneficial for human health, however, excessive UV radiation can cause various human diseases as well as strong destruction to the output of crops and the lifespan of buildings. [1b,3a,4] Therefore, an efficient detection of UV radiation is of significant importance in widespread applications, for example, chemical, environmental, and biological analysis or warning, astronomical investigation, and optical communication. [1c,5] For forewarning UV radiation with high-efficiency, a wide variety of UV PDs such as photomultiplier and silicon diode, have been extensively investigated and applied in the past decades. Nevertheless, there are intrinsic imperfections for the present commercial PDs, such as fragile, large volume, and excessive cost, which are obstacles when meeting the growing requirement of miniaturized and reliable UV detection devices for portable or shipped applications. In recent years, the development of semiconductor-based PDs that work according to the photoelectric effect has received great research interest. [1b,3a,6] In this scenario, a delicate selection of suitable materials with efficient morphological, microstructural, and photoelectrical characteristics plays a key role in the construction of PDs with high-performance. Generally, the PDs work following several different physical mechanisms, that is, surface plasma-wave-assisted effect, photoconductive effect, photothermoelectric effect, and photovoltaic effect, which have been systematically demonstrated in the previous report. [7] More recently, a new generation of wide-bandgap semiconductors including the classification of nitrides (GaN, AlN, BN, etc.), carbides (SiC, diamond, etc.), sulfides (ZnS, etc.), oxides (ZnO, Ga 2 O 3 , TiO 2 , etc.), halide perovskites (e.g., CH 3 NH 3 PbCl 3 ), [8] and their combinations, is emerged as the most attractive material candidates for constructing high-performance UV PDs, owing to their unique advantages, for instance low permittivity, high breakdown electric-fields, good thermal conductivity, high electron saturation rates, excellent radiation resistance, and their appropriate spectral range for UV response. [1d] In addition, the photoelectric conversion processes of the semiconductorbased PDs can be generally described by the behaviors of charge carriers, such as their generation, separation, transportation, and extraction. [9] Therefore, any factor that influences the photon-generated carrier behaviors should be the key parameter for further tuning their photodetecting performances. It As a wide-bandgap semiconductor material, titanium dioxide (TiO 2 ), which possesses three crystal polymorphs (i.e., rutile, anatase, and brookite), has gained tremendous attention as a cutting-edge material for application in the environment and energy fields. Based on the strong attractiveness from its advantages such as high stability, excellent photoelectric properties, and lowcost fabrication, the construction of high-performance photodetectors (PDs) based on TiO 2 nanostructures is ...

Polypyrrole Film Deposited-TiO2 Nanorod Arrays for High Performance Ultraviolet Photodetectors

“…Chemosensors 2022, 10, x FOR PEER REVIEW 5 of 13 The optical properties of pure TiO 2 and nPPy-TiO 2 nanocomposites were then characterized by UV-Vis absorption spectra and a photoluminescence spectrum. As shown in Figure 5a, pure TiO 2 displayed an absorption edge around 420 nm, implying a band gap of 3.0 eV of rutile TiO 2 [33]. The absorption edges of nPPy-TiO 2 nanocomposites were around 410 nm, which suggested that PPy changed the band gap of the prepared TiO 2 .…”

Advances in Self-Powered Ultraviolet Photodetectors Based on P-N Heterojunction Low-Dimensional Nanostructures

“…An ultraviolet (UV) photodetector is a kind of photo-electronic device that converts a light signal to an electrical signal by using the photoelectric effect of semiconductors. As an important device for both military and civil use, ultraviolet (UV) photodetectors have attracted much attention in recent years because of their vast applications in military early warning, communication sensing, environmental monitoring, disease diagnosis, and so on [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Because UV radiation is generally divided into three bands (UVA: 320–400 nm, UVB: 280–320 nm, and UVC: 10–280 nm) according to the standards of the International Commission on Illumination [ 11 ], over the past two decades, wide-bandgap inorganic semiconductors (such as ZnO, TiO 2 , SnO 2 , ZnS, GaN, Ga 2 O 3 , etc.)…”

Self-powered ZnO-based pyro-phototronic photodetectors: impact of heterointerfaces and parametric studies

“…11 Owing to their facile miniaturized integration along with their strong radiation response to harsh environment sustainability, wide band gap (E g ) semiconductors have turned out to be potential candidates. 12 Among the various semiconductors with a wide E g , such as ZnS, 13,14 TiO 2 , 15,16 GaN, 17 SiC, 18 ZnSe, 19 ZnTe, 20 In 2 Te 3 , 21 MoS 2 , [22][23][24] Nb 2 O 5 , 25,26 ZnO, 27 NiO, 28,29 SnO 2 , [30][31][32] K 2 Nb 8 O 21 , 33 etc., which have been studied for UV PD applications, zinc oxide (ZnO, E g E 3.37 eV) has attracted huge attention due to its large room-temperature (RT) excitonic binding energy (B60 meV), low collision ionization coefficient, environmentally stable chemical and radiation properties, and so on. [34][35][36] ZnO has thus been the champion material for UV detection with extensive research over time.…”