The role of surface electron accumulation and bulk doping for gas-sensing explored with single-crystalline In2O3 thin films

Rombach, Julius; Papadogianni, Alexandra; Mischo, Markus; Cimalla, V.; Kirste, Lutz; Ambacher, O.; Berthold, Theresa; Krischok, S.; Himmerlich, Marcel; Selve, Sören; Bierwagen, Oliver

doi:10.1016/j.snb.2016.03.079

Cited by 45 publications

(64 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The structural properties of the investigated In 2 O 3 film are summarized in Figure : The symmetric out‐of‐plane XRD 2θ‐ω scan in Figure a shows the sole presence of different diffraction orders of (111) lattice planes of the yttrium‐stabilized zirconia (YSZ) substrate and the In 2 O 3 film. In agreement with our previous work showing the cube‐on‐cube relation of the In 2 O 3 film to the YSZ(111) substrate, this confirms the single‐crystalline nature of the investigated In 2 O 3 (111) film. The ω rocking curve shown in Figure b has a full‐width at half maximum of 0.15°, indicating a low degree of tilt mosaic, which suggests a comparably high crystalline quality for a heteroepitaxial film.…”

Section: Resultsmentioning

confidence: 99%

“…This process was similar to the growth recipe described in ref. . Structural and electronic transport properties of the film were also investigated as described in ref.…”

Section: Methodsmentioning

confidence: 99%

“…Structural and electronic transport properties of the film were also investigated as described in ref. and are summarized in Figure . Van der Pauw–Hall measurements at room temperature indicate n ‐type conductivity with a sheet resistance of 490 Ω sq −1 due to ≈1.5 × 10 14 cm −2 electrons (corresponding to an average bulk electron concentration of ≈4 × 10 18 cm −3 ) with an electron mobility of ≈84 cm 2 V −1 s −1 .…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

Jovic

Moser

Papadogianni

et al. 2019

Small

Self Cite

View full text Add to dashboard Cite

Transparent conducting oxides (TCO) have integral and emerging roles in photovoltaic, thermoelectric energy conversion, and more recently, photocatalytic systems. The functional properties of TCOs, and thus their role in these applications, are often mediated by the bulk electronic band structure but are also strongly influenced by the electronic structure of the native surface 2D electron gas (2DEG), particularly under operating conditions. This study investigates the 2DEG, and its response to changes in chemistry, at the (111) surface of the model TCO In2O3, through angle resolved and core level X‐ray photoemission spectroscopy. It is found that the itinerant charge carriers of the 2DEG reside in two quantum well subbands penetrating up to 65 Å below the surface. The charge carrier concentration of this 2DEG, and thus the high surface n‐type conductivity, emerges from donor‐type oxygen vacancies of surface character and proves to be remarkably robust against surface absorbents and contamination. The optical transparency, however, may rely on the presence of ubiquitous surface adsorbed oxygen groups and hydrogen defect states that passivate localized oxygen vacancy states in the bandgap of In2O3.

show abstract

Section: Resultsmentioning

confidence: 99%

“…This process was similar to the growth recipe described in ref. . Structural and electronic transport properties of the film were also investigated as described in ref.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

Jovic

Moser

Papadogianni

et al. 2019

Small

Self Cite

View full text Add to dashboard Cite

show abstract

“…For this purpose, flat, epitaxial In 2 O 3 (111) films are characterized as model system. While the conductometric gas response is smaller than in optimized polycrystalline films our approach removes the complexity of grain boundaries from the problem . In this study, we investigate changes in surface properties by gas adsorption measured by X‐ray and ultraviolet photoelectron spectroscopy (XPS and UPS).…”

Section: Introductionmentioning

confidence: 99%

Towards Understanding the Cross‐Sensitivity of In₂O₃ Based Ozone Sensors: Effects of O₃, O₂ and H₂O Adsorption at In₂O₃(111) Surfaces

Berthold

Katzer

Rombach

et al. 2017

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

The interaction of ozone, oxygen, and water molecules with the (111) surface of indium oxide grown by plasma‐assisted molecular beam epitaxy is investigated. In order to characterize the adsorption and charge transfer mechanisms taking place at ozone‐sensitive In2O3 films and to determine the effect of humidity, we study the chemical and electronic surface properties using photoelectron spectroscopy. Clean surfaces are prepared by vacuum annealing and subsequently exposed to O3, O2, or H2O in serial adsorption sequences. After ozone and oxygen interaction, the same adsorbate species are detected and both molecules reduce the surface electron density, resulting in a decrease of film conductance. However, the quantitative changes of adsorbate coverage, band bending, surface electron concentration, and work function indicate a much higher reactivity of the surface with ozone. In contrast, if the surface is exposed to water, the resulting adsorbates have a different spectroscopic signature and do not significantly alter surface band bending and electron concentration. The effects of ozone/oxygen interaction are weakened if the surface was pre‐exposed to water. These results indicate that water adsorbates occupy surface sites that are consequently not available for ozone interaction and that humidity influences the device sensitivity but not its selectivity toward oxidizing gases.

show abstract

“…Second, the good gas sensing for NO x of the In 2 O 3 sensor can be ascribed to the single crystal In 2 O 3 and its own nanosheet structure which have a benecial effect on the performance of the In 2 O 3 sensor. 47,48 The ideal structure is considered to be single crystal, because such gas sensing materials can exhibit high electron conductivities, and have abundant interfacial active sites and excellent stability. 49,50 When the porous coupled with single crystallinity provides for the ease of gas diffusion and more active sites for the formation of reactive oxygen species.…”

Section: Gas Sensing Performances and Sensing Mechanismmentioning

confidence: 99%

Highly active and porous single-crystal In₂O₃ nanosheet for NO_x gas sensor with excellent response at room temperature

et al. 2017

View full text Add to dashboard Cite

Porous single-crystal In 2 O 3 nanosheet (ps-In 2 O 3 NS) was designed and prepared through a method of calcination after liquid reflux. Compared with the other In 2 O 3 with different surface morphologies, the ps-In 2 O 3 NS has gas sensing properties towards NO x at room temperature. Gas sensing data strongly demonstrate that this porous single-crystal In 2 O 3 nanosheet exhibits a distinguished response (89.48) and fast response time (16.6 s) to 97.0 ppm NO x . Meanwhile, the ps-In 2 O 3 NS sensor presents a favorable linearity and good selectivity, and the detection of NO x is down to ppb levels at room temperature. The enhancement of the sensing response is attributed to the porous, single-crystal and two dimensional nanosheet structure of the synthesized ps-In 2 O 3 NS, which has much higher BET surface area, effective gas diffusion of slit pores and thus provides more active sites for the reaction of NO x with surface-adsorbed oxygen ions. This work would be important for the low-cost and high performance of the In 2 O 3 material with highly promising applications in gas sensors.

show abstract

The role of surface electron accumulation and bulk doping for gas-sensing explored with single-crystalline In2O3 thin films

Cited by 45 publications

References 44 publications

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

Towards Understanding the Cross‐Sensitivity of In₂O₃ Based Ozone Sensors: Effects of O₃, O₂ and H₂O Adsorption at In₂O₃(111) Surfaces

Highly active and porous single-crystal In₂O₃ nanosheet for NO_x gas sensor with excellent response at room temperature

Contact Info

Product

Resources

About

The role of surface electron accumulation and bulk doping for gas-sensing explored with single-crystalline In2O3 thin films

Cited by 45 publications

References 44 publications

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications

Towards Understanding the Cross‐Sensitivity of In2O3 Based Ozone Sensors: Effects of O3, O2 and H2O Adsorption at In2O3(111) Surfaces

Highly active and porous single-crystal In2O3 nanosheet for NOx gas sensor with excellent response at room temperature

Contact Info

Product

Resources

About

Towards Understanding the Cross‐Sensitivity of In₂O₃ Based Ozone Sensors: Effects of O₃, O₂ and H₂O Adsorption at In₂O₃(111) Surfaces

Highly active and porous single-crystal In₂O₃ nanosheet for NO_x gas sensor with excellent response at room temperature