Mechanism of the photocatalytic activity of p-Si(100)/n-ZnO nanorods heterojunction

Hòa, Nguyễn Thị; Cuong, Vuong Van; Lâm, Nguyễn Đình

doi:10.1016/j.matchemphys.2017.10.070

Cited by 20 publications

(17 citation statements)

References 22 publications

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“…The rectifying J-V behavior of ZnO/p-Si composites was also previously reported by some groups under various experimental conditions. [36][37][38][39][40][41][42] Our findings imply that the n-ZnO/p-Si(100)…”

Section: J-v Characteristics At Room Temperaturementioning

confidence: 94%

Modified SILAR Grown ZnO Films on p‐Si(100) with Enhanced Charge Separation for UV Light Sensing Application

Ontolan¹,

Vequizo

Yamakata

et al. 2021

Physica Status Solidi (a)

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Herein, the growth of pristine ZnO nanostructures thin film on p‐Si(100) by modified successive ionic layer adsorption‐reduction method, revealing significant improvement in the charge collection for ultraviolet light detection, is reported. The deposited ZnO exhibits spindle‐like and hexagonal structure that grows preferentially along the c‐axis. Two‐probe electrical measurements validate the rectifying nature of the constructed n‐ZnO/p‐Si(100), revealing a substantial 11.3‐fold increase in photocurrent at room temperature under 375 nm irradiation at +3 V working voltage. The drastic increase in photocurrent is linked to efficient charge separation caused by charge transfer and band bending effects, as indicated by microsecond time‐resolved absorption measurements, providing useful information for device development.

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Section: J-v Characteristics At Room Temperaturementioning

confidence: 94%

Modified SILAR Grown ZnO Films on p‐Si(100) with Enhanced Charge Separation for UV Light Sensing Application

Ontolan¹,

Vequizo

Yamakata

et al. 2021

Physica Status Solidi (a)

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“…Therefore, fabrication of efficient n-p heterojunctions has been proposed and attempted with the different levels of success during the last few years [4, 17, 20–22]. Specifically, it was found that the fabricated n-p heterojunctions could sufficiently reduce the recombination rate of the photo-generated electron/hole pairs with the following enhancement of the overall photocatalytic activity [1, 23, 24]. Thus, the combination of p- and n- type semiconductor oxides has paved the way for the further development of n-p heterojunctions and optimization of their photocatalytic capabilities [25].…”

Section: Introductionmentioning

confidence: 99%

Wafer-Scale Fabrication of Sub-10 nm TiO2-Ga2O3 n-p Heterojunctions with Efficient Photocatalytic Activity by Atomic Layer Deposition

Han

Xia

et al. 2019

Nanoscale Res Lett

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Wafer-scale, conformal, two-dimensional (2D) TiO 2 -Ga 2 O 3 n-p heterostructures with a thickness of less than 10 nm were fabricated on the Si/SiO 2 substrates by the atomic layer deposition (ALD) technique for the first time with subsequent post-deposition annealing at a temperature of 250 °C. The best deposition parameters were established. The structure and morphology of 2D TiO 2 -Ga 2 O 3 n-p heterostructures were characterized by the scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), etc. 2D TiO 2 -Ga 2 O 3 n-p heterostructures demonstrated efficient photocatalytic activity towards methyl orange (MO) degradation at the UV light ( λ = 254 nm) irradiation. The improvement of TiO 2 -Ga 2 O 3 n-p heterostructure capabilities is due to the development of the defects on Ga 2 O 3 -TiO 2 interface, which were able to trap electrons faster. Graphical Abstract

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“…Firstly the higher growth temperatures used for CTR-VPT growth can lead to an increased thickness SiO2 layer between the Si and ZnO, retarding current flow. 62 A further contribution may come from heterojunction formation between the p-Si (substrate) and the CBD ZnO layer with lower thickness; thus, when the p-Si and the n-ZnO make electrical contact with each other their Fermi levels will equalise, leading to the shift of their conduction and valence bands; 35 Another possible source for the lower photocurrent of the ZnO/CTR-VPT sample is the presence of defects on surface of the ZnO/CTR-VPT, which may lead to relatively low efficiency separation of the photogenerated carriers. 60 XPS data presented previously indicate slight differences in surface chemistry between the CBD and CTR-VPT samples.…”

Section:  (Degree)mentioning

confidence: 99%

“…It is also worth mentioning that, for applications in PEC, no work has been reported in the literature using ZnO grown on (inexpensive and widely available) Si substrates. Hoa et al 35 fabricated ZnO nanorods on glass and Si substrates by a hydrothermal method and investigated the PC activity of this structure for degradation of Rhodamine B under UV light irradiation. The results indicated that the Si/ZnO nanorod heterojunction exhibits higher photocatalytic activity compared to that of a glass/ZnO nanorod junction.…”

Section: Introductionmentioning

confidence: 99%

“…Among 6 various hybrid forms, when a ZnO/Si heterojunction is formed, photogenerated charge carriers can be separated by an internal electric field and consequently photocarrier recombination is inhibited, contributing to the improvement of PC activity. 35,36 Therefore, further investigations of the Si/ZnO nanorod heterojunction in PEC is a promising area of research, which remains largely unexplored.…”

Section: Introductionmentioning

confidence: 99%

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Photoelectrocatalytic Degradation of Methylene Blue Using ZnO Nanorods Fabricated on Silicon Substrates

Rosa

Cavalcante

Silva

et al. 2020

j nanosci nanotechnol

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ZnO nanorods were grown on silicon (Si) substrates by two techniques: (i) Chemical Bath Deposition (CBD) and (ii) a CBD seed layer combined with Carbothermal Reduction Vapor Phase Transport (CTR-VPT). The structured ZnO nanorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle measurments. The photoelectrochemical property of ZnO nanorods were analyzed by linear voltammetry under UV-ABC light excitation. Using the ZnO nanorod samples as photoanodes, the removal of methylene blue (MB) as a representative organic compound was studied by the photoelectrocatalytic (PEC) technique applying a potential (E) of 0.6 V. For comparison purposes, experiments were performed under the same conditions using photocatalysis (PC), direct photolysis and using samples of pure Si (support material) as working electrodes in PEC. XRD analyses of ZnO prepared by both methods showed the expected ZnO wurtzite phase and a preferred c-axial orientation in the growth of the nanorods. The presence of ZnO was further confirmed by XPS and contact angle measurements showed that ZnO grown by CBD (ZnO/CBD) had a slightly hydrophobic behavior while ZnO grown by CTR-VPT (ZnO/CTR-VPT) is hydrophilic. Both ZnO sample types were shown to be photoactive, 3 with ZnO/CBD showing higher resultant photocurrent compared to ZnO/CTR-VPT. For the degradation of MB 53% of the compound was removed using ZnO/CBD as a working electrode, while using the ZnO/CTR-VPT electrode led to a removal of 43% of MB. However, direct photolysis alone removed 39% of the MB. The lower removal of MB using ZnO/CTR-VPT samples was related to surface dissociation during the degradation process. The results show that ZnO nanorods prepared by the CBD techique are a promising photoelectrode for PEC applications. Our data also indicate that CTR-VPTgrown nanorods produce uniform nanorod arrays, but this uniform nanostructure deposit does not lead to any increase in PEC activity.

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Mechanism of the photocatalytic activity of p-Si(100)/n-ZnO nanorods heterojunction

Cited by 20 publications

References 22 publications

Modified SILAR Grown ZnO Films on p‐Si(100) with Enhanced Charge Separation for UV Light Sensing Application

Modified SILAR Grown ZnO Films on p‐Si(100) with Enhanced Charge Separation for UV Light Sensing Application

Wafer-Scale Fabrication of Sub-10 nm TiO2-Ga2O3 n-p Heterojunctions with Efficient Photocatalytic Activity by Atomic Layer Deposition

Photoelectrocatalytic Degradation of Methylene Blue Using ZnO Nanorods Fabricated on Silicon Substrates

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