Indium Molybdenum Oxide Research Articles

SPR-Based Fiber Optic Sensor Using IMO Thin Film: Towards Wide Wavelength Tunability From Visible to NIR

Due to existence of free electrons, conducting metal oxides (CMOs) such as indium molybdenum oxide, can support surface plasmon resonance (SPR) at the interface of CMO and dielectric. This research provides, theoretically, the first implementation of indium molybdenum oxide (IMO) as plasmonic layer in SPR fiber optic sensor. We demonstrate how changing the oxygen contents during IMO layer deposition could tune the operational wavelength of sensing probe in a wide range from visible to NIR which has a great significance in many biological and chemical environmental applications. Moreover, sensitivity and figure of merit of the proposed sensor have been calculated and compared for IMO thin films prepared at different oxygen contents.

Luminescent Electrochromic Devices for Smart Windows of Energy-Efficient Buildings

To address the challenges of the next generation of smart windows for energy-efficient buildings, new electrochromic devices (ECDs) are introduced. These include indium molybdenum oxide (IMO), a conducting oxide transparent in the near-infrared (NIR) region, and a NIR-emitting electrolyte. The novel electrolytes are based on a sol-gel-derived di-urethane cross-linked siloxane-based host structure, including short chains of poly (ε-caprolactone) (PCL(530) (where 530 represents the average molecular weight in g mol−1). This hybrid framework was doped with a combination of either, lithium triflate (LiTrif) and erbium triflate (ErTrif3), or LiTrif and bisaquatris (thenoyltrifluoroacetonate) erbium (III) ([Er(tta)3(H2O)2]). The ECD@LiTrif-[Er(tta)3(H2O)2] device presents a typical Er3+ NIR emission around 1550 nm. The figures of merit of these devices are high cycling stability, good reversibility, and unusually high coloration efficiency (CE = ΔOD/ΔQ, where Q is the inserted/de-inserted charge density). CE values of −8824/+6569 cm2 C−1 and −8243/+5200 cm2 C−1 were achieved at 555 nm on the 400th cycle, for ECD@LiTrif-ErTrif3 and ECD@LiTrif-[Er(tta)3(H2O)2], respectively.

Optical and Electrical Properties of Indium Molybdenum Oxide Thin Films by the Co-Sputtering Method

This work was supported in part by the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) with a grant funded by the Korean government (MOTIE) (No. 2013010010120) and by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2014R1A2A1A11053936).

Charge mobility increase in indium-molybdenum oxide thin films by hydrogen doping

The increase of charge mobility in transparent conductive indium molybdenum oxide (IMO) films is correlated with the presence of hydroxyl groups. The introduction of H2 in the chamber during sputtering deposition compensates the excess charge introduced by cationic Mo doping of indium oxide either by oxygen or hydroxyl interstitials. Films present a linear increase of carrier mobility correlated with H2 content only after vacuum annealing. This behavior is explained because vacuum annealing favors the removal of oxygen interstitials over that of hydroxyl groups. Since hydroxyl groups offer lower effective charge and smaller lattice distortions than those associated with interstitial oxygen, this compensation mechanism offers the conditions for the observed increase in mobility. Additionally, the short-range order around molybdenum is evaluated by extended X-ray absorption fine structure (EXAFS) spectroscopy, showing that Mo4+ is placed at the In site of the indium oxide.

Thin-film transistors based on Zinc Oxide channel layer and Molybdenum doped Indium Oxide transparent electrodes

ABSTRACTThin-film transistors (TFT) were fabricated at room-temperature (RT) utilizing zinc oxide (ZnO) channel and indium molybdenum oxide (IMO) electrodes. The common bottom-gate TFTs were fabricated on commercially available thermal silicon oxide (100 nm thick) coated silicon wafers. A total of 100 devices were made in a 1 inch square area as 10 × 10 matrix, by varying the channel width and length, between 5 µm and 300 µm. Output and transfer characteristics of the fabricated devices were extracted from a semiconductor parameter analyzer. A threshold voltage (VTh) of 10 V and an ION/IOFF ratio of 1 × 10-5 were obtained. The impact of channel dimensions on the device performance was investigated, confirming that the saturation current (Isat) is directly proportional to the channel width (W), and inversely proportional to channel length (L), in agreement with field effect device theory.

Impact of glycerol on Zinc Oxide based thin film transistors with Indium Molybdenum Oxide electrodes

ABSTRACTThin-film transistors (TFT) were fabricated at a room-temperature (RT) with zinc oxide (ZnO) channel and indium molybdenum oxide (IMO) electrodes. To isolate the gate oxide and gate electrode influence on the device performance, common gate configuration on a commercial substrate with thermal SiO2 (100 nm) was selected. A threshold voltage (VTh) of 10 V and ION/IOFF ratio of 1 × 10-5 were obtained. Once the reference data was taken transistors were exposed to glycerol. Temporary changes in device characteristics were observed due to the influence of glycerol, a low conductivity medium. To exclude the possibility of sugar alcohol being the main conductor, measurement on dummy transistor electrode was performed retaining the distance between probes. The TFT device under test revealed ten times higher drain current but also a change in threshold voltage and leakage current. Transistors under glycerol influence were always open with the positive gate bias.

High-Speed and High-Light Output Power of InGaAs/GaAs HBLETs With an InMoO<sub>x</sub> Contact

A high-speed and high-light-output-power InGaAs/GaAs heterojunction bipolar light-emitting transistors (HBLETs) at 968-nm wavelength employing indium molybdenum oxide (IMO) contact are demonstrated in this letter. The IMO contact exhibits a low electrical resistivity of \(3.5 \times 10^{\mathrm {\mathbf {-4}}}~\Omega \) -cm accompanied with an extremely high optical transmittance of 99% at 968 nm, which can be ascribed to larger valence difference between In 3+ matrix and Mo 6+ dopants. As compared to HBLET with conventional AuGe contact, HBLET with IMO contact shows a higher forward voltage and higher series resistance. However, at the corresponding injection current level, HBLET with IMO contact produces a light output power with a rate of \(5.7~\mu \) W/mA, which is twice of \(2.7~\mu \) W/mA for HBLET with AuGe contact. In addition, HBLET with IMO contact exhibits a 3-dB optical bandwidth of 649 MHz, which is correlated to a carrier recombination lifetime of 245 ps. The successful incorporation of an IMO contact into an HBLET can improve the optical output extraction significantly without the expense of losing modulation speed.

Temperature-resistant high-infrared transmittance indium molybdenum oxide thin films as an intermediate window layer for multi-junction photovoltaics

For optimal performance, the intermediate window layer in multijunction photovoltaics should transmit as much light as possible to guarantee maximum device efficiency. In this work, we demonstrate that indium molybdenum oxide (IMO) is a more suitable intermediate layer, compared to indium tin oxide (ITO), as it would absorb significantly less infrared light with comparable electrical conductivity once integrated into a multijunction solar cell. In fact, we show that IMO optoelectronic properties are virtually unchanged by the typical thermal budgets used in solar absorber deposition processes used in low-cost high-performance multijunction photovoltaics (e.g. CuInGaSe2). Specifically, IMO and ITO thin films were reactively sputtered onto glass substrates at 150°C, then subjected to a vacuum annealing process (550°C, 2h) identical to that of co-evaporated copper gallium diselenide (CGSe), a candidate material for the top absorber in multijunction cells. We found that annealing substantially reduces the infrared transmittance of ITO starting at 900nm, reducing by 2.5% per 100nm, while IMO only started experiencing a reduction at 1400nm and decaying more slowly at 1.6% per 100nm. Furthermore, the resistivity of IMO was comparable to that of ITO after annealing. The resilience of IMO to such high temperature processes show that it has potential to enhance the performance of multijunction devices.

Transparent conducting indium molybdenum oxide films by pulsed laser ablation

Highly transparent and conducting molybdenum oxide (2, 3, 4wt%) doped indium oxide thin films are prepared using pulsed laser ablation. XRD and AFM analysis show that at higher MoO3 doping concentration (>3wt%) inhibits grain growth due to the presence of Mo atoms at grain boundaries. The average size of the crystallites increases with MoO3 doping up to 3% and thereafter decreases. The doped films exhibited high values of optical transmittance and low values of electrical resistivity compared to undoped films. Beyond 3wt% MoO3 doping, the optical and electrical properties slightly decline. The observed band gap widening in the films can be attributed to Moss–Burstein effect. All the films show intense PL emission in the UV–visible region.

Deposition of Transparent Indium Molybdenum Oxide Thin Films and the Application for Organic Solar Cells

In this study, we systematically investigate the effects of post-annealing on the structural, electrical, and optical characteristics of indium molybdenum oxide (IMO) films. The incorporation of IMO films into organic solar cells (OSCs) is further studied. The optimum content of Mo is 2.36 wt %. Furthermore, a significant improvement in crystallinity, surface morphology, electrical resistivity, and optical transmittance is observed after thermal annealing. The lowest resistivity is obtained with post annealing at 300 °C for 140 s. The OSC utilizing the IMO electrode shows an efficiency of up to 3.77%, which is higher than that of the OSC utilizing the ITO electrode. The diffusion length of the carriers in the OSC is approximately 10 nm. Thus, the higher efficiency can be explained by the smoother surface morphology of the post annealed IMO electrode. These results indicate that the novel IMO films with superior material properties have enormous potential applications for solar cells.

Deposition of Transparent Indium Molybdenum Oxide Thin Films and the Application for Organic Solar Cells

Deposition of Transparent Indium Molybdenum Oxide Thin Films and the Application for Organic Solar Cells

Thin-Film Transistors Based on Indium Molybdenum Oxide Semiconductor Layers Sputtered at Room Temperature

Thin-film transistors (TFTs) were fabricated using a 20-nm-thick indium molybdenum oxide (IMO) semiconductor layer at room temperature. The grazing incidence x-ray diffraction patterns confirmed that the deposited films are amorphous. The average transmittance (400–2500 nm) and the optical band gap are <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\sim$</tex></formula> 88% and 3.95 eV, respectively. The TFTs fabricated on glass substrates showed a saturation mobility of 4.0 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{cm}^{2}/\hbox{V}\cdot\hbox{s}$</tex></formula> with an <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$I_{\rm ON}/I_{\rm OFF}$</tex></formula> ratio of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{2} \times \hbox{10}^{3}$</tex></formula> and a threshold voltage of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex></formula> 1.1 V, which are encouraging preliminary results in order to develop IMO as high-performance semiconductor layer.

Structural, optical and electrical properties of indium–molybdenum oxide thin films prepared by spray pyrolysis

AbstractMolybdenum doped indium oxide (IO) thin films were deposited on the Coring F1737 glass substrates at 400 °C by spray pyrolysis technique. The Mo doping was varied between 0 and 4 at.%. The films were characterized by their structural, electrical and optical properties. The films are confirmed to be cubic bixbyite In2O3 with a strongest orientation along (222) for 0.5 at.% Mo, which is shifted to (400) plane when the Mo doping is increased to ≥1.2 at.%. The films deposited with 0.5 at.% Mo showed high mobility of ∼90 cm2/Vs, resistivity of ∼6.8 × 10−4 Ω cm and carrier concentration of ∼1.01 × 1020 cm−3 with &gt;∼73% transmittance in the visible range between 500 and 800 nm. The transmittance is well extended into near infrared region.

Thickness Dependence of Optoelectrical Properties of Mo‐Doped In2O3 Films Deposited on Polyethersulfone Substrates by Ion‐Beam‐Assisted Evaporation

Indium molybdenum oxide (IMO) films were deposited onto the polyethersulfone (PES) substrates by ion‐beam‐assisted evaporation (IBAE) deposition at low temperature in this study. The effects of film thickness on their optical and electrical properties were investigated. The results show that the deposited IMO films exhibit a preferred orientation of B(222). The electrical resistivity of the deposited film initially reduces then subsequently increases with film thickness. The IMO film with the lowest resistivity of 7.61 × 10−4 ohm‐cm has been achieved when the film thickness is 120 nm. It exhibits a satisfactory surface roughness Rpv of 8.75 nm and an average visible transmittance of 78.7%.

Indium molybdenum oxide thin films: A comparative study by two different RF sputtering systems

AbstractIndium molybdenum oxide thin films were deposited using different radio‐frequency sputtering units on glass substrates at room temperature from an In2O3 (95 wt.%): Mo (5 wt.%) target. The film thickness ranges between 160 and 275 nm. The chamber volume of Unit‐1 was ∼2.4 times larger than that of Unit‐2. Apart from the chamber volume, a significant difference between the two units was the sputtering pressure. The films were characterized by their structural, morphological, optical, and electrical properties. A strong reflection from (222) plane was obtained for the ∼275 nm thick films deposited in Unit‐1. The films deposited with &lt;275 nm thickness and those deposited in Unit‐2 are close to amorphous with a small crystalline fraction. The surface of the films deposited in Unit‐1 is comprised of randomly arranged crystallites, which is restructured with the increasing film thickness to become a well defined “rice field” like structure (275 nm thick). The films deposited in Unit‐2 are comprised of many holes on the surface that is presumably due to back sputtering. The average visible transmittance calculated in the wavelength between 400 and 800 nm ranges from 70 to 82%. The optical band gap is found to vary between 3.80 and 3.86 eV. The lowest bulk resistivity of the films deposited in Unit‐1 was increased from ∼4.06 × 10−3 to 4.07 × 10−1 Ω cm when deposited in Unit‐2. The carrier concentration was decreased from 1.31 × 1020 to 1.03 × 1018 cm−3 but the Hall mobility increased from 11.7 to 15.0 cm2 V−1 s−1.

RF sputtered wide work function indium molybdenum oxide thin films for solar cell applications

Indium molybdenum oxide (IMO) thin films were deposited by RF magnetron sputtering on glass substrates at room temperature. The deposition and argon partial pressures were maintained at 6.0 × 10 −1 Pa and 3.0 × 10 −1 Pa, respectively. The oxygen partial pressure (OPP) was varied in the range 1.0–6.0 × 10 −3 Pa. The films were sputtered at 40 W for 30 min using the target consisted In 2O 3 (98 wt%): Mo (2 wt%). The films are polycrystalline with a slight preferential orientation along (2 2 2) plane. The crystallinity is increased with the increasing OPP. The negative sign of Hall coefficient confirmed the n-type conductivity. A maximum mobility ∼19 cm 2 V −1 s −1 is obtained for the films deposited with OPP of 3.6 × 10 −3 Pa. The average visible transmittance calculated in the wavelength ranging 500–800 nm is ranging between 2% and 77%. The optical band gap calculated from the absorption data is varied between 3.69 and 3.91 eV. A striking feature is that the work function of the films is wide ranging 4.61–4.93 eV. A possibility of using the produced IMO films as transparent conducting oxide in photovoltaic applications such as organic solar cells is discussed in this article.

Effect of annealing on the properties of RF sputtered indium molybdenum oxide thin films

Indium molybdenum oxide thin films radio-frequency sputtered at room temperature on glass were studied as a function of oxygen volume percentage. The as-deposited films were post-annealed in the temperature range of 300–500°C in oxidizing (open air) and reducing (N2:H2 gas) atmospheres for 1h. The as-deposited amorphous films become crystalline on post-annealing irrespective of the annealing conditions. In most cases, the (222) diffraction line is emerged as the high intensive peak. The films annealed at ⩾400°C in N2:H2 show a carrier concentration >1020cm−3. The better electrical properties are obtained for the films post-annealed at 300°C. The optical transmittance of the as-deposited films varies between 10% and 85% depending on the deposition and annealing conditions. Atomic force microscope analysis reveal that the films annealed at 300°C are composed of closely packed crystallites (size of which varies between 5nm and 150nm) whose size varies noticeably when the annealing temperature is raised to 400°C. On the other hand, the surface of the films annealed at 500°C becomes rougher, with the RMS roughness varying between 2.00nm and 16.97nm. The surface of the films deposited in the presence of oxygen shows metal like features when annealed at ⩾400°C in N2:H2 that is attributed to the segregation of indium. Further, the segregation of In is substantiated from the scanning electron microscope analysis of these samples.

Effects of oxygen gas flow rate and ion beam plasma conditions on the opto-electronic properties of indium molybdenum oxide films fabricated by ion beam-assisted evaporation

The purpose of the present work is to experimentally study the effects of the oxygen gas flow rate and ion beam plasma conditions on the properties of indium molybdenum oxide (IMO) films deposited onto the polyethersulfone (PES) substrate. Crystal structure, surface morphology, and optoelectronic properties of IMO films are examined as a function of oxygen gas flow rate and ion beam discharge voltage. Experimental results show that the IMO films consist of a cubic bixbyite B-In 2O 3 single phase with its crystal preferred orientation alone B(222). Mo 6+ ions are therefore considered to partially substitute In 3+ sites in the deposit. Under-controlled ion bombardment during deposition enhances the reaction among those arriving oxygen and metal ion species to condense into IMO film and facilitates a decreased surface roughness of IMO film. The film with ultimate crystallinity and the lowest surface roughness is obtained when the oxygen flow rate of 3 sccm and the discharge voltage of 110 V are employed. This results in the lowest electrical resistivity due mainly to the increased Hall mobility and irrelevant to carrier concentration. The lowest electrical resistivity of 8.63 × 10 − 4 ohm-cm with a 84.63% transmittance at a wavelength of 550 nm can be obtained, which satisfies the requirement of a flexible transparent conductive polymer substrate.

Some studies on highly transparent wide band gap indium molybdenum oxide thin films rf sputtered at room temperature

Transparent wide band gap indium molybdenum oxide (IMO) thin films were rf sputtered on glass substrates at room temperature. The films were studied as a function of sputtering power (ranging 40–180 W) and sputtering time (ranging 2.5–20 min). The film thickness was varied in the range 50–400 nm. The as-deposited films were characterized by their structural (XRD), morphological (AFM), electrical (Hall Effect measurements) and optical (visible-NIR spectroscopy) properties. XRD studies revealed that the films are amorphous for the sputtering power ≤100 W and the deposition time ≤5 min, and the rest are polycrystalline with a strong reflection from (222) plane showing a preferential orientation. A minimum bulk resistivity of 2.65×10−3 Ω cm and a maximum carrier concentration of 4.16×1020 cm−3 are obtained for the crystalline films sputtered at 180 W (10 min). Whereas a maximum mobility (19.5 cm2 V−1 s−1) and average visible transmittance (∼85%) are obtained for the amorphous films sputtered at 80 W and 100 W respectively for 10 min. A minimum transmittance (∼18%) was obtained for the crystalline films sputtered at 180 W (∼305 nm thick). The optical band gap was found varying between 3.75 and 3.90 eV for various sputtering parameters. The obtained results are analyzed and corroborated with the structure of the films.

Effect of base and oxygen partial pressures on the electrical and optical properties of indium molybdenum oxide thin films

Indium molybdenum oxide thin films were RF sputtered at room temperature on glass substrates with a reference base pressure of 7.5 × 10 − 4 Pa. The electrical and optical properties of the films were studied as a function of oxygen partial pressures (OPP) ranging from 1.5 × 10 − 3 Pa to 3.5 × 10 − 3 Pa. The obtained data show that the bulk resistivity of the films increased by about 4 orders of magnitude (from 7.9 × 10 − 3 to 7.6 × 10 1 Ω-cm) when the OPP increased from 1.5 × 10 −3 to 3.5 × 10 − 3 Pa, and the carrier concentration decreased by about 4 orders (from 1.77 × 10 20 to 2.31 × 10 16 cm − 3 ). On the other hand, the average visible transmittance of 30.54% of the films (brown colour; OPP = 1.5 × 10 − 3 Pa) was increased with increasing OPP to a maximum of 80.47% (OPP = 3.5 × 10 − 3 Pa). The optical band gap calculated from the absorption edge of the transmittance spectra ranges from 3.77 to 3.88 eV. Further, the optical and electrical properties of the films differ from those deposited at similar conditions but with a base pressure lower than 7.5 × 10 − 4 Pa.