Structure and Opto-electrochemical Properties of ZnO Nanowires Grown on <i>n</i>-Si Substrate

Ladanov, Mikhail; Ram, Manoj K.; Matthews, Garrett; Kumar, Ashok

doi:10.1021/la200584j

Cited by 44 publications

(24 citation statements)

References 22 publications

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“…Since Fujishima and Honda reported the photoelectrochemical water splitting in 1972 [6], various metal oxides such as TiO 2 [6,7], Fe 2 O 3 [8,9], and ZnO [10,11,12] have drawn much attention due to their composition of low-cost, and environmentally friendly elements. However, these metal oxide semiconductors except Fe 2 O 3 only allow absorbing UV light range in the solar spectrum, so their solar-to-fuel conversion efficiencies for water splitting are still low.…”

Section: Introductionmentioning

confidence: 99%

In situ measurement of photostability of CdSe/CdS/ZnO nanowires photoelectrode for photoelectrochemical water splitting

Choi

Yim

Baek

et al. 2015

Sensors and Actuators B: Chemical

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Section: Introductionmentioning

confidence: 99%

In situ measurement of photostability of CdSe/CdS/ZnO nanowires photoelectrode for photoelectrochemical water splitting

Choi

Yim

Baek

et al. 2015

Sensors and Actuators B: Chemical

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“…The XRD pattern from the sample (Figure 2b) also shows the crystal orientation in the NWs with dominate orientation for (002) at 2θ = 34.9°, which is an indication for the c-axis being vertical to the substrate. 33 First, the device was tested in the dark by scanning the voltage of the bottom electrode from −3 V to +2 V, while the top electrode was grounded. As shown in Figure 3, the I−V curve demonstrated a rectifying characteristic.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Photoelectric Memory Effect in an Organic Bulk Heterojunction Device

Santhanakrishna

Takshi

2015

J. Phys. Chem. C

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We report on a memory effect observed in an inverted bulk heterojunction organic photovoltaic device, where the electron-collecting electrode is ZnO nanowires grown on an indium tin oxide (ITO) substrate. The device presented a unique response to light by switching from a rectifying behavior in the dark to a resistive response under illumination. After cessation of light, the device slowly stabilized back to its rectifying nature after ∼270 min, introducing a volatile photoelectric memory effect. The reversibility of the response is verified through multiple cycles of light exposure and placing the device in the dark. The device is also illuminated with different light intensities to study the photovoltaic response through I−V characterization. It is found that the time constant associated with the transition between the rectifying and resistive characteristics is independent from the light intensity. Further study revealed that there is a hysteresis loop in the I−V curve in the dark, but the loop vanished in the resistive mode under illumination. A mechanism based on oxygen absorption−desorption has been suggested to explain the observed effect. Such a memory effect can be used in various optoelectronic devices to save the optical information for an extended time. ■ INTRODUCTIONOrganic electronic devices (OEDs) provide a sustainable solution for renewable energy sources, sensors, display systems, memory devices, and various other applications due to its low cost materials, solution processing manufacturing, and minimal environmental impact. 1 In particular, the market for organic optoelectronic devices is quite large. 2,3 The effect of light on organic semiconductors has been studied extensively for the application of converting solar energy to electrical energy in organic photovoltaic devices (OPVs). 4,5 Although a semiconductor is able to generate electron−hole pairs upon absorption of photons, to separate charges in an OPV, it is required to use two different organic semiconductors as the electron donor and the electron acceptor. 3 To enhance the efficiency of generating charges from photons, a bulk heterojunction structure is recommended in which a blend of the two semiconductors is used as the photoactive layer of the device. 6−8 Among various combinations of the materials, poly 3-hexylthiophene (P3HT) and phenyl-C 61 -butyric acid methyl ester (PCBM) are the most common electron donor and acceptor materials, respectively. 4,9,10 To enhance the efficiency in a device, the electrons and holes are transferred to the device electrodes selectively by using hole blocking and electron blocking layers between the photoactive layer and the electrodes. The thickness and energy structure of the blocking layers are critical in designing an efficient OPV. 11 One of the most promising structures for making efficient OPVs is to use PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrenesulfonate) as the electron blocking layer and a thin layer of a metal oxide (or metal sulfide) as the hole blocking layer. 12−14 Using a ...

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“…It is worth noting that the supersaturation reaction may also take place. These chemical reactions can be summarized as follows [29][30][31][32]:…”

Section: Methodsmentioning

confidence: 99%

High electron mobility and low carrier concentration of hydrothermally grown ZnO thin films on seeded a-plane sapphire at low temperature

Jayah¹,

Yahaya²,

Mahmood³

et al. 2016

Nano Online

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Hydrothermal zinc oxide (ZnO) thick films were successfully grown on the chemical vapor deposition (CVD)-grown thick ZnO seed layers on a-plane sapphire substrates using the aqueous solution of zinc nitrate dehydrate (Zn(NO 3 ) 2 ). The use of the CVD ZnO seed layers with the flat surfaces seems to be a key technique for obtaining thick films instead of vertically aligned nanostructures as reported in many literatures. All the hydrothermal ZnO layers showed the large grains with hexagonal end facets and were highly oriented towards the c-axis direction. Photoluminescence (PL) spectra of the hydrothermal layers were composed of the ultraviolet (UV) emission (370 to 380 nm) and the visible emission (481 to 491 nm), and the intensity ratio of the former emission (I UV ) to the latter emission (I VIS ) changed, depending on both the molarity of the solution and temperature. It is surprising that all the Hall mobilities for the hydrothermal ZnO layers were significantly larger than those for their corresponding CVD seed films. It was also found that, for the hydrothermal films grown at 70°C to 90°C, the molarity dependences of I UV /I VIS resembled those of mobilities, implying that the mobility in the film is affected by the structural defects. The highest mobility of 166 cm 2 /Vs was achieved on the hydrothermal film with the carrier concentration of 1.65 × 10 17 cm −3 grown from the aqueous solution of 40 mM at 70°C.

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Structure and Opto-electrochemical Properties of ZnO Nanowires Grown on n-Si Substrate

Cited by 44 publications

References 22 publications

In situ measurement of photostability of CdSe/CdS/ZnO nanowires photoelectrode for photoelectrochemical water splitting

In situ measurement of photostability of CdSe/CdS/ZnO nanowires photoelectrode for photoelectrochemical water splitting

Photoelectric Memory Effect in an Organic Bulk Heterojunction Device

High electron mobility and low carrier concentration of hydrothermally grown ZnO thin films on seeded a-plane sapphire at low temperature

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