Gas sensing properties of novel CuO nanowire devices

Steinhauer, Stephan; Brunet, E.; Maier, Thomas; Mutinati, Giorgio C.; Köck, Anton; Freudenberg, Oliver; Gspan, Christian; Grogger, Werner; Neuhold, Alfred; Resel, Roland

doi:10.1016/j.snb.2012.09.034

Cited by 181 publications

(98 citation statements)

References 40 publications

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“…3(a). Increased electrical resistance in the presence of water vapor was found, which is in accordance with results on CuO nanowire 8,24 and thick film 23 gas sensor devices. The interaction of H 2 O molecules with CuO surfaces is expected to lead to the formation of terminal hydroxyl groups and a decrease of ionosorbed oxygen species.…”

supporting

confidence: 89%

“…1 Cupric oxide (CuO) nanowires, most commonly showing p-type conductivity and a band gap around 1.4 eV, 2 have been used in applications such as field effect transistors, 3 optoelectronics, 4,5 and, in particular, gas sensing. [6][7][8] Low-frequency conductance fluctuations are commonly observed in metals and semiconductors and have been utilized as indicator for material/technology quality and device reliability, 9 as well as for the characterization of generation-recombination centers. 10 In the field of sensor devices, low-frequency noise measurements have been performed in order to gain information on their detection limit.…”

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confidence: 99%

“…In this letter, we report on 1/f noise measurements of single CuO nanowire devices in dry synthetic air and in the presence of water vapor; the latter was chosen as target gas due to its importance for gas sensing applications in ambient atmosphere. Measurement results at a typical operation temperature for CuO nanowire gas sensors 8,19 (350 C) are compared and analyzed in terms of a core-shell nanowire model, considering Hooge mobility fluctuations. 9 Increased 1/f noise in the presence of water vapor is attributed to the interaction of H 2 O molecules with the metal oxide nanowire surface.…”

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confidence: 99%

“…The Ni layer between CuO and Au was around 7-10 nm thick and the lattice spacings indicated that it was oxidized to NiO, presumably during the thermal annealing process. The CuO nanowire devices were assembled with microheaters and tested in an automated gas measurement setup as reported previously 8 using a constant total gas flow of 1000 sccm. Electrical characterization results of a representative single CuO nanowire device (diameter 143 nm, contact spacing 1.9 lm) are shown in Fig.…”

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Low-frequency noise characterization of single CuO nanowire gas sensor devices

Steinhauer

Köck

Gspan

et al. 2015

Applied Physics Letters

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Low-frequency noise properties of single CuO nanowire devices were investigated under gas sensor operation conditions in dry and humid synthetic air at 350 °C. A 1/f noise spectrum was found with the normalized power spectral density of current fluctuations typically a factor of 2 higher for humid compared to dry atmosphere. A core-shell nanowire model is proposed to treat the noise as parallel combination of gas-independent bulk and gas-dependent surface noise components. The observed increase in 1/f noise in the presence of water vapor is explained in terms of Hooge's mobility fluctuation model, where the increased surface noise component is attributed to carrier scattering at potential fluctuations due to hydroxyl groups at the nanowire surface.

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confidence: 89%

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confidence: 99%

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Low-frequency noise characterization of single CuO nanowire gas sensor devices

Steinhauer

Köck

Gspan

et al. 2015

Applied Physics Letters

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“…Metal oxide (MOx) semiconductors have become promising gas sensors due to their low cost, short response time, long life and wide range target selectivity [5]. Therefore, numerous researchers presented the investigation results on the following oxides: CuO [6], In 2 O 3 [7], WO 3 [8], TiO 2 [9], V 2 O 5 [10], Fe 2 O 3 [11], MoO 3 [12], ZnO [13], etc. Different metal oxide based materials have different reaction activation to the target gases.…”

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Thermal and Electrical Investigation on LTCC Gas Sensor Substrates

Rydosz¹,

Maziarz²,

Pisarkiewicz³

et al. 2016

IJIEE

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Abstract-Metal Oxide (MOx) semiconductor gas sensors typically operate at temperatures of few hundred Celsius degrees and consume hundreds of miliwatts of power. It is therefore, essential, to investigate the heat flux and power consumption in MOx sensors, especially designed for applications in battery-powered devices. The work presents the thermal and electrical investigations on LTCC substrates (Low Temperature Cofired Ceramic) as a base material for gas sensors. A novel shape of substrates with reduced heat capacity is showed. The sensor temperature was modulated with a pulsed heater voltage, therefore decreasing the average power consumption.Index Terms-LTCC, gas sensors, thermal investigation, metal oxide. I. INTRODUCTIONDuring the last several decades, considerable advances in gas sensor technology have been achieved in various applications such as: safety devices [1], environmental monitoring [2], air quality control [3], and health diagnosis [4]. Metal oxide (MOx) semiconductors have become promising gas sensors due to their low cost, short response time, long life and wide range target selectivity [5]. Therefore, numerous researchers presented the investigation results on the following oxides: CuO [6] [12], ZnO [13], etc. Different metal oxide based materials have different reaction activation to the target gases. The chemical and physical processes of working sensors are well known [14], but still sensors behaviours are investigated. However, it is well known that the operating temperature is the most important factor that influences the performance of semiconductor gas sensors. The MOx sensors usually work in o C temperature range [15]. To provide such elevated temperatures a heater is usually embedded into gas sensors substrates. Depending on expected working temperature and substrate built, the consumed power can reach the level of hundreds of miliwatts. The power consumption of gas sensors can be reduced by using a pulsed operation mode, gas sensitive layers working at lower temperatures, changes in substrate design and materials [16]. The search for suitable substrate for Manuscript received December 9, 2014; revised February 13, 2016 Fig. 1 shows the concept of a complete gas sensing device which consists of few elements such as: gas sensitive layer, gas sensor substrate, package, front-end electronics and signal processing. For developed gas sensors the authors used TO-5 package. The electrical connections between sensors pads and case pins were welded with a 0.5 mm thick Pt wire. Fig . 2 shows the gas sensors based on LTCC substrate mounted in TO-5 package. The response of MOx sensors is influenced by various factors, i.e. gas concentration, temperature, gas flow, humidity etc. To provide suitable temperature in a sensitive region, an uniform temperature distribution is required. Therefore, the temperature distribution is a crucial issue that have to be taken into consideration. The temperature distribution in a modified gas sensor substrates was previously reported in [21]. Briefly, it is...

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