Coaxial p-Si/n-ZnO nanowire heterostructures for energy and sensing applications

Gad, Alaaeldin; Hoffmann, Martin; Hernández-Ramírez, Francisco; Prades, Joan Daniel; Shen, Hao; Mathur, Sanjay

doi:10.1016/j.matchemphys.2012.05.034

Cited by 17 publications

(10 citation statements)

References 32 publications

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“…Under illumination with solar light (AM1. 5), an open circuit voltage (Voc) is induced by the build-in potential at the p-n heterojunction [2,13,14] that is used as a self-generated signal for the sensor. To ensure a strong and measurable Voc signal even under low illumination conditions, every device contained several diodes connected in series by evaporated gold contacts (9, 16 or 26 diodes; see Figure 1c).…”

Section: Figure 1amentioning

confidence: 99%

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

et al. 2014

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Low power consumption and reliable selectivity are the two main requirements for gas sensors to be applicable in mobile devices. [1] These technological platforms, e.g. smart phones or wireless sensor platforms will facilitate personalized detection of environmental and health conditions, and hence becoming the basis of the future core technology of ubiquitous sensing. Even today, health control as well as environmental monitoring is relying on immobile and complex detection systems with very limited availability in space and time. Recent works have shown promising concepts to realize selfpowered gas sensors that are capable of detecting gases without the need of external power sources to Submitted to 2 activate the sensor-gas interaction or to actively generate a read out signal. [2,3] These sensors drastically reduce power consumption compared to conventional semiconductor gas sensors and additionally reduce the required space for integration. All these attempts so far were based on purely nano structured inorganic metal oxide sensor materials that provide a good sensitivity towards different gases due to their high surface-to-volume ratio. However, due to their non-selective sensing mechanism based on oxygen vacancy-gas interactions, these purely inorganic sensors cannot accomplish a meaningful gas selectivity. [4,5] High selectivities towards single gas species have been recently reported via modifying the inorganic surface of nanostructured semiconductors with a defined organic functionality. [6][7][8][9] Theoretical simulations based on ab-initio density functional theory (DFT) for a system composed of SnO2 NWs modified with a defined self assembled monolayer (SAM) elucidated the reason for the high selectivity of such gas sensor: the energetic position of the SAM-gas frontier orbitals with respect to the NW Fermi level have been identified to be the crucial factor to ensure an efficient charge transfer upon gas-SAM binding interactions and thus to sense or discriminate a certain gas species. [7] The high flexibility of organic surface modifications in terms of functional groups as well as their sterical and electronic structure possibly might enable the targeted design of various specific gas sensors. However, all organic surface modified sensor systems so far are based on compact conductometric or field effect transistor (FET) sensor concepts that still require a remarkable amount of energy to generate a sensor signal (e.g. by applying a source-drain current). Up to date, none of the semiconductor based gas sensor systems could accomplish both, the selfpowered/low powered sensor operation and highly selective gas detection within a single and compact device.In this work, we present a semiconductor based gas sensor concept that combines the two substantial requirements of mobile gas sensing in a singular sensor device: self-powered operation combined with high gas selectivity. Beyond the combination of self-powered sensing and high selectivity, also a very high sensitivity could also been demonst...

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Section: Figure 1amentioning

confidence: 99%

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

et al. 2014

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“…Especially, electronic devices, such as transistors, memristors, field emission devices, and sensors all require controlled assembly and integration of nanomaterials at desired locations (i.e., electrodes) on the devices. The most common method is the placement of single 1D nanomaterial followed by metal contact formation with e‐beam lithography and metal lift‐off process . Although this method allows the fabrication of single 1D nanomaterial device with accurate position control of metal contacts, it is very time‐consuming and low throughput.…”

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Focused Energy Field Method for the Localized Synthesis and Direct Integration of 1D Nanomaterials on Microelectronic Devices

Yang

Kim

et al. 2014

Advanced Materials

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“…) or oxides (TeO 2 , ZnO, etc. ) also shows effective improvement in response magnitude and selectivity. Nevertheless, little efforts on SiNWs with C‐S heterostructure have been performed so far.…”

Section: Introductionmentioning

confidence: 89%

Highly sensitive NO₂ sensors based on core‐shell array of silicon nanowires/polypyrrole and new insight into gas sensing mechanism of organic/inorganic hetero‐contact

et al. 2019

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Uniform core‐shell hetero‐array of polypyrrole‐wrapped silicon nanowires (LNWs/PPy C‐S nanowires) with enhanced gas‐sensing response at room temperature was prepared via a two‐step process. The aligned silicon nanowires were first formed by metal‐assisted chemical etching (MACE). To achieve a loose silicon nanowires (LNWs) array facilitating the uniform deposition of PPy shell on whole wire surface, a repeated MACE treatment was further developed based on reoxidation of the MACE‐produced Ag dendrites. The PPy‐shell with adjustable thickness was then formed uniformly on the LNWs via vapor chemical polymerization (VCP) of pyrrole monomer (Py). The gas sensor based on the well‐defined LNWs/PPy C‐S heteronanowires array exhibits about 8.2 times response enhancement to 5 ppm NO2 gas compared with the pristine one at room temperature. Very low detection resolution of 50 ppb NO2 is observed when PPy shell has thickness of about 10 nm. The organic/inorganic C‐S composite of LNWs/PPy nanowires shows a different characteristic of shell thickness effect on sensing response from the general semiconductor oxides‐based C‐S sensor; much thinner PPy shell is extremely preferred for higher sensing response. A sensing mechanism model was proposed to demonstrate the featured effect of organic shell thickness on sensing behavior of LNWs/PPy C‐S heteronanowires. POLYM. COMPOS., 40:3275–3284, 2019. © 2019 Society of Plastics Engineers

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Coaxial p-Si/n-ZnO nanowire heterostructures for energy and sensing applications

Cited by 17 publications

References 32 publications

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

Focused Energy Field Method for the Localized Synthesis and Direct Integration of 1D Nanomaterials on Microelectronic Devices

Highly sensitive NO₂ sensors based on core‐shell array of silicon nanowires/polypyrrole and new insight into gas sensing mechanism of organic/inorganic hetero‐contact

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Coaxial p-Si/n-ZnO nanowire heterostructures for energy and sensing applications

Cited by 17 publications

References 32 publications

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

Focused Energy Field Method for the Localized Synthesis and Direct Integration of 1D Nanomaterials on Microelectronic Devices

Highly sensitive NO2 sensors based on core‐shell array of silicon nanowires/polypyrrole and new insight into gas sensing mechanism of organic/inorganic hetero‐contact

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Highly sensitive NO₂ sensors based on core‐shell array of silicon nanowires/polypyrrole and new insight into gas sensing mechanism of organic/inorganic hetero‐contact