Aluminum-doped Zinc Oxide Research Articles

Numerical study of mid-infrared broadband perfect absorber based on dielectric/aluminium doped zinc oxide multilayer films

We propose a lithography-free wide-angle polarization-insensitive ultra-broadband absorber by using multilayer films consist of five pairs of aluminium doped zinc oxide (AZO) and a dielectric film which is supposed to be fabricated on glass substrate. The absorption spectrum of the proposed model is calculated by using transfer matrix method. The analytic results show that the absorptivity is larger than 95% with normal incidence light in the wavelength range from 7.5μm to 20μm and having high transmittance at the visible wavelength range from 0.4μm to 0.8μm range. Further, the effect of incident angle and polarization on the absorption spectrum are also investigated. The absorption spectrum of the proposed design is highly tunable on changing the damping constant of the AZO film. The electric field and magnetic distributions at different wavelengths show that the absorption is mainly originated due to the constructive interference of electromagnetic waves in the multilayer films. Such physical mechanism of broadening bandwidth based on increasing the carrier concentration of the highly visible transparent conducting films have pave a new direction for the design of tunable broadband absorber in different frequency band. Meanwhile, this broadband absorber is a good candidate for the potential applications in daytime radiation cooling system in the mid-infrared frequency band and also used as transparent conducting electrode in solar cell applications.

Synthesis and study of the impact of calcination duration on the properties of Al4(ZnO)96 nanoparticles

Aluminium doped zinc oxide (Al4(ZnO)96) nanoparticles were synthesized using new sogel method at 40 °C, with zinc acetate dihydrate (Zn(CH3COO)2·2 H2O) and aluminium nitrate nonahydrate (Al(NO3)3·9 H2O) as precursors. The samples underwent analysis using various structural and optical techniques to investigate the effect of calcination duration on the properties. Prolonged calcination durations led to a significant reduction of oxygen at the grain boundaries, influencing particle size and crystallization. According to TEM-histogram analysis, the most probable size for 28.5 % of nanoparticles fell within the range of 15–20 nm, which aligns closely with the estimated particle size determined by XRD analysis. The material displayed a significant direct bandgap of approximately 3.283 eV, which increased with the duration of calcination. The band gap was affected by changes in phase, strain, and particle size, attributed to the presence of defect states and a substantial concentration of localized states. Additionally, the material exhibited excellent chemical stability and a significantly high binding energy. Moreover, the optical bandgap widened as the width of the Urbach tails in the localized states decreased with an increase in the duration of calcination.

Microstructural and optoelectronic properties of sputtered Al:ZnO films and Al:ZnO/Cu bilayer structures: Effects of substrate and Cu thickness

In this study, using a multi-source confocal radio frequency magnetron sputtering system, we synthesized aluminum doped zinc oxide (AZO) single layers and AZO/Cu bilayers on glass and crystalline quartz substrates with a constant AZO thickness of 65 nm and variable Cu bottom layers with a thickness of 4–13 nm. The microstructural, morphological, optical, and electrical characteristics of all samples were investigated using a variety of spectroscopic techniques. The X-ray diffraction results show that all films prepared on both substrates have a hexagonal wurtzite crystal structure and exhibit the preferred orientation along the (002) plane with some microstructural variations. The atomic force microscopy images revealed that the thickness of the Cu layer and substrate type greatly affect the films' topography and surface roughness. The transmittance spectra indicate that the single AZO layer on both substrates possess the highest average visible transmission; however, all the samples deposited on glass substrates show greater transmittance than that on quartz. Photoluminescence analysis put into evidence a decrease in ultraviolet emission with Cu thickness for both substrates, with intensities varying according to substrate type. Hall Effect measurements reveal that all samples have n-type conductivity as well as that Cu thickness has a significant impact on their electrical characteristics. Moreover, a higher value of the figure of merit is achieved with the AZO/Cu bilayer structure grown on a glass substrate with 13 nm of Cu layer thickness.

Investigation of the Structural, Electrical, and Optical Properties of Co-Precipitation-Synthesized Aluminum-Doped ZnO Nanostructures

Abstract: This study examines the Structural, Electrical, and Optical characteristics of Zinc Oxide substituted with aluminum (AlxZn1-xO; x = 0, 0.02, 0.04, 0.06, 0.08). The coprecipitation technique is used to synthesize the powders, and X-ray diffraction (XRD) is used to analyze the powders' structural properties. Field Emission Scanning Electron Microscopy (FESEM) is used to study the morphological characteristics of the produced powders. The UV-visible absorbance spectrum (UV-Vis.) was used to assess the particles' optical characteristics. Using photoluminescence (PL) spectra, the effects of morphology on the optical and electrical characteristics of produced powders were examined. The XRD patterns verified that a single-phase hexagonal wurtzite structure formed for each sample. The powders' FESEM pictures reveal how, as the Al concentration increases, the particles' morphology alters from hexagonal to spherical. The synthesized samples have crystallite sizes between 19 and 26 nm. The predictable variations noticed with Al3+ concentration are consistent with Al3+ incorporation into the ZnO lattice, as confirmed by the UV-Vis spectroscopy measurements.

Assessing the Effect of Twisting and Twisting Fatigue on ZnO:Al Thin Film Performance on PEN and PET Substrates.

This study examines the electromechanical characteristics of aluminium-doped zinc oxide (AZO) films. The films were produced using the RF magnetron sputtering process with a consistent thickness of 150 nm on various polymer substrates. The study focuses on assessing the electro-mechanical failure processes of coated segments using flexible substrates, namely polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), with a specific emphasis on typical cracking and delamination occurrences. This examination involves conducting twisting deformation together with using standardised electrical resistance measurements and optical microscope monitoring instruments. It was found that the crack initiation angle is mostly dependent on the mechanical mismatch between the coating and substrate. Higher critical twisting angle values are observed for the AZO/PEN film during twisting testing. Relative to the perpendicular plane of the untwisted sample, it was found that cracks initiated at a twist angle equal to 42° ± 2.1° and 38° ± 1.7° for AZO/PEN and AZO/PET, respectively, and propagated along the sample length. SEM images indicate that the twisting motion results in deformation in the thin film material, leading to the presence of both types of stress in the film structure. These discoveries emphasise the significance of studying the mechanical properties of thin films under different stress conditions, as it can impact their performance and reliability in real-world applications. The electromechanical stability of AZO was found to be similar on both substrates during fatigue testing. Studying the electromechanical properties of various material combinations is important for selecting polymer substrates and predicting the durability of flexible electronic devices made from polyester.

In situ aluminum doped zinc oxide thin films by pulse electrodeposition for the all-electrodeposited cadmium-free copper indium diselenide solar cells

Pulse electrodeposition was used to produce aluminum doped zinc oxide (AZO) films, which were then used to construct an all-electrodeposited cadmium-free (Cd-free) Copper Indium Diselenide (CISe) solar cell. Aluminum was added into the films during the deposition process by positioning an Aluminum (Al) metal foil into the electrolyte. Energy Dispersive Spectrometry (EDS) elemental mapping confirmed the incorporation of Al into the films. According to X-Ray Diffraction (XRD) patterns, the aluminum doped zinc oxide films have a wurtzite hexagonal crystal structure, only with (002) planes indicating phase purity. The impedance analysis of the annealed device with electrodeposited aluminum doped zinc oxide revealed that it had better charge transfer resistance than the as-deposited device.

Mica-based β-Ga2O3 photodetector: Enabling solar-blind deep-ultraviolet detection with flexibility and transparency

Flexible, transparent solar-blind deep-ultraviolet photodetectors (SBPDs) based on Ga2O3 are gaining momentum for a wide range of future military and civilian applications. However, the fabrication of flexible, transparent SBPDs based on β-Ga2O3 faces challenges due to the inability of commonly used polymer substrates to withstand the high temperatures needed for growth. In this study, the challenge was addressed by producing highly transparent β-phase Ga2O3 thin films on mica substrates using rf magnetron sputtering and annealing techniques. Subsequently, flexible and transparent SBPDs were developed utilizing a metal-semiconductor-metal (MSM) configuration, combining the β-Ga2O3 thin films with an aluminum-doped zinc oxide (AZO) transparent conductive layer. The device with full transparency to visible light revealed a remarkable responsivity of 1.25 A/W and rapid photoresponse rates of 0.18/0.06 s under 254 nm illumination, placing their performance at the forefront among β-Ga2O3-based flexible SBPDs. Notably, even after undergoing numerous mechanical bending tests at varying diameters and cycling counts, the device maintained consistent stability across all performance parameters. This study highlights the potential of mica-based β-Ga2O3 photodetectors for enabling flexible and transparent solar-blind deep-ultraviolet detection.

High‐Performance Transparent Electron‐Selective Contact for Crystalline Silicon Solar Cells

AbstractHigh‐efficiency silicon solar cells featuring doped silicon layer‐based carrier‐selective contacts suffer from optical losses due to parasitic absorption. In this work, a high‐performance electron‐selective contact with high transparency is presented, consisting of intrinsic hydrogenated amorphous silicon (a‐Si:H) passivation layer, atomic‐layer‐deposited conductive magnesium oxide (MgOx) and low‐work‐function aluminium doped zinc oxide (AZO). The a‐Si:H/MgOx/AZO stack is demonstrated to be an excellent and transparent electron‐selective contact on c‐Si, featuring a small contact resistivity (ρc) of 56.0 mΩ cm2 and a low saturation current density (J0) of 2.9 fA cm−2 simultaneously. By the implementation of the a‐Si:H/MgOx/AZO front contact, a high power conversion efficiency (PCE) of 23.3% is achieved on silicon heterojunction (SHJ) solar cells, featuring an absolute short‐circuit current density (Jsc) and PCE gain of 1.3 mA cm−2 and 1.2%, respectively, compared to the conventional phosphorus‐doped silicon layer‐based electron‐selective contact. Moreover, a state‐of‐the‐art PCE of 22.8% is obtained on c‐Si solar cells with dopant‐free asymmetric heterocontacts on both sides, featuring an a‐Si:H/MgOx/AZO front contact and an a‐Si:H/vanadium oxide (VOx) rear contact.

Construction of an electrochemical platform with carbon nanotubes and aluminium doped zinc oxide nanoparticles for the sensitive determination of sunset yellow

AbstractSunset yellow, a synthetic colorant and used to improve the texture and the appearance of food samples, can adversely affect humans. The development of a sensitive method to analyse food products for the accurate determination of sunset yellow is of importance for the level of risk to human health and thus food safety. The present study aimed to prepare a voltammetric method for the precise detection of sunset yellow content in a commonly consumed powdered beverage and pharmaceutical products. For this purpose, a sensitive method utilizing a voltammetric platform was constructed by modifying a glassy carbon electrode (GCE) with carbon nanotubes (MWCNTs) and aluminium doped zinc oxide (AZO). Cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) measurements indicated that the proposed voltammetric platform (GCE/MWCNTs/AZO) possessed high electro‐active surface area and lower value of charge transfer resistance (Rct) and therefore, could serve as a promising sensing material. The GCE/MWCNTs/AZO system improved voltammetric behaviour of sunset yellow at an accumulation time of 210 s and indicated good electrocatalytic activity due to high synergistic effect between MWCNTs and AZO nanoparticles. This method of analysis exhibited a dynamic working range from 4.0×10−9 to 7.5×10−6 M with a limit of detection (LOD) of 9.5×10−10 M for sunset yellow. The GCE/MWCNTs/AZO system was successfully utilized for the electroanalysis of beverages and pharmaceuticals for detection of sunset yellow. Voltammetric measurements indicate that the GCE/MWCNTs/AZO system enables good accuracy and high precision for the determination of sunset yellow.

Aluminum-doped zinc oxide thickness controllable wavelengths in visible light and high responsivity devices using interrupted flow atomic layer deposition

In this study, we develop a highly sensitive visible light photodetector that utilizes a thin-film structure composed of low-cost aluminum-doped zinc oxide (AZO) and n-type silicon. The AZO thickness can be adequately controlled to fit the different wavelengths of interest for photodetectors in the visible light range using interrupted flow atomic layer deposition (ALD). This in situ aluminum doping method ensures a uniform aluminum distribution within the AZO thin films and effectively increases the internal film reflections and photoresponsivity. The Schottky interface with n-type silicon is created by degenerated AZO due to the lower Fermi level, and visible light can effectively penetrate the underlying depletion zone. Optical simulation of the high conductivity of AZO indicated that the optimal thickness was 54.6, 65.8, and 91.7 nm for devices illuminated with 450 nm blue, 525 nm green and 700 nm red light, respectively. Hall effect measurements confirmed that the AZO film can achieve a low resistivity of 5 × 10–4 Ω-cm and high carrier concentration of 3 × 1020 cm−3 at a suitable precursor ratio. Additionally, AZO films offer multifunctionality by providing optical antireflective properties and forming Schottky junctions with n-type silicon to enable photoelectric conversion. This multifunctional role of AZO was experimentally validated through electrical, optical, and optical-to-electrical experiments, which showed that the optimized device can reach an optical responsivity of approximately 10.7 AW−1 at specific visible light wavelengths. The significant photoelectrical conversion efficiency and simple thin-film structure design facilitate future applications in light intensity measurement, such as in colorimetry or fluorometry.

Effect of transparent conductive layers on the functionality of liquid crystal devices: Comparison of AZO, FTO and ITO

The integration of highly transparent and highly conductive layers plays a crucial role in the advancement of various next-generation optoelectronic technologies. Here, we demonstrate a comparison of optical, electrical and wettability properties of Aluminum-doped Zinc Oxide (AZO) deposited by Atomic Layer Deposition Technique (ALD) with commercially available Fluorine-doped Tin Oxide (FTO) and Indium-doped Tin Oxide (ITO) Transparent Conductive Oxide (TCO) layers. Their impact on the electro-optical modulation behavior when applied in Liquid Crystal (LC) device assemblies are compared and discussed. The AZO layers performance prove that are fully competitive to the commercial FTO and ITO layers and verify the high demand for the next generation indium tin oxide (ITO)-free technology.

Aluminum oxide, cobalt aluminum oxide, and aluminum-doped zinc oxide nanoparticles as an effective antimicrobial agent against pathogens

Since the clock of antimicrobial resistance was set, modern medicine has shed light on a new cornerstone in technology to overcome the worldwide dread of the post-antimicrobial era. Research organizations are exploring the use of nanotechnology to modify metallic crystals from macro to nanoscale size, demonstrating significant interest in the field of antimicrobials. Herein, the antimicrobial activities of aluminum oxide (Al2O3), cobalt aluminum oxide (CoAl2O4), and aluminum doped zinc oxide (Zn0.9Al0.1O) nanoparticles were examined against some nosocomial pathogens. The study confirmed the formation and characterization of Al2O3, CoAl2O4, and Zn0.9Al0.1O nanoparticles using various techniques, revealing the generation of pure nanoscale nanoparticles. With inhibition zones ranging from 9 to 14 mm and minimum inhibitory concentrations varying from 4 mg/mL to 16 mg/mL, the produced nanoparticles showed strong antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Meanwhile, the bactericidal concentrations ranged from 8 mg/mL to 40 mg/mL. In culture, Zn0.9Al0.1O NPs demonstrated a unique ability to inhibit the development of nosocomial infections with high bactericidal activity (8 mg/mL). Transmission electron microscope images revealed changes in cell shape, bacterial cell wall morphology, cytoplasmic membrane, and protoplasm due to the introduction of tested nanoparticles. These results pave the way for the use of these easily bacterial wall-piercing nanoparticles in combination with potent antibiotics to overcome the majority of bacterial strains' resistance.

Influence of a Magnetic Field on the Structure, Morphology and Gas Sensing Characteristics of ZnO: Al Thin Films Prepared by Pulsed Laser Ablation

In this work, aluminium-doped zinc oxide (AZO) nanostructure at 0.3 wt% and 0.5 wt% Al was synthesized using the pulse-laser ablation technique in liquid(PLAL) using pulsed Nd: YAG laser of a fundamental wavelength of (1064 nm). The process was done in the absence and presence of an external magnetic field. The deposited AZO nanostructures by drop-casting on etched-Si wafers were examined by different techniques. The XRD test illustrates enhancing the crystallinity of the prepared thin films by applying an external magnetic field. The FESEM images displayed the change of nanostructure to nano-sheets of high surface area after using a 77.2 mT permanent magnet placed behind the target during the ablation process. The gas sensor based on the AZO nanostructures has higher sensitivity against NO2 than H2S. Increasing the Al ratio from 0.3 wt% to 0.5 wt% changed the properties of the prepared samples to have small porosity and small surface area, which negatively affected the properties of the sensor

The Impact of Temperature and Power Variation on the Optical, Wettability, and Anti-Icing Characteristics of AZO Coatings

The structural, wettability, and optical characteristics of aluminum-doped zinc oxide (AZO) thin films were studied with the objective of understanding the impact of deposition power and deposition temperature. Thin films were deposited using a radio frequency (RF) magnetron sputtering technique. The power output of the RF was augmented from 200 to 260 W, and the temperature was increased from 50 to 200 °C, which led to the development of a (002) peak for zinc oxide. The study of film thickness was carried out using the Swanepoel envelope method from data obtained through the UV-Vis spectrum. An increase in surface roughness value was shown to be connected with fluctuations in temperature as well as increases in deposition power. The findings revealed that as deposition power and temperature increased, the value of optical transmittance decreased, ranging from 70% to 90% based on the deposition parameters within the range of wavelengths that extend from 300 to 800 nm. The wettability properties of the samples were studied, and the maximum contact angle achieved was 110°. A Peltier apparatus was utilised in order to investigate the anti-icing capabilities, which revealed that the icing process was slowed down 3.38-fold. This work extends the understanding of the hydrophobicity and anti-icing capabilities of AZO thin films, specifically increasing both attributes which provide feasible options for purposes requiring resistance to ice.

Experimental and theoretical aspects of the growth of vertically aligned CNTs by CCVD on AZO substrate

An efficient and reproducible growth of vertically aligned carbon nanotubes by CCVD requires accurate and specific setting of the synthesis parameters and the properties of catalyst thin layers. In this work, the growth of vertically aligned carbon nanotubes onto AZO (= aluminum doped zinc oxide) glass substrate covered by Al2O3 and Fe-Co catalyst layer system is presented. Investigation of the effect of catalyst composition and synthesis temperature on CVD growth revealed the optimum condition of the synthesis. The analysis of as-prepared samples by SEM, TEM and Raman spectroscopy was carried out to prove the structure and quality of carbon deposit. Theoretical considerations have supported speculative ideas about the role of the support layer, the transformation of the catalyst layer in the presence of hydrogen gas and the growth mechanism of carbon nanotubes. The mechanism of CNT growth is modelled and the order of magnitude of experimentally observed vertical linear growth rate of CNT (several nm/s) is reproduced.

MORPHOLOGICAL, OPTICAL PROPERTIES AND ELECTRONIC STRUCTURE OF ZnO THIN FILMS DOPED WITH ALUMINUM

This paper presents the results of investigation of aluminum-doped zinc oxide thin films obtained by radio-frequency magnetron deposition on a glass substrate. It was shown by energy dispersion X-ray spectroscopy that the average aluminum content in the thin films was 0.2–0.8 at.%. An increase in the average grain size with increasing aluminum concentration was shown, and column-like growth of the films was established using microscopic images. Investigation of the electronic structure showed a redistribution of intensity in the O 1s spectrum with aluminum doping. The valence band spectra were also obtained, and theoretical calculations were performed within the framework of density functional theory to better understanding the results. Using a spectrophotometer, the transparency of the films obtained after aluminum doping was shown to increase. With the help of the Tauc method, the band gap was determined to be 3.41 eV, while DFT calculations showed a band gap of 1.25 eV.

Synergistic Enhancement of Efficient Perovskite/Quantum Dot Tandem Solar Cells Based on Transparent Electrode and Band Alignment Engineering

AbstractPerovskite‐based tandem solar cells have demonstrated high potential for overcoming the Shockley–Queisser limit. Routine bandgap (RBG, ≈1.55 eV) perovskites have achieved a perfect balance between efficiency and stability. The narrow bandgap (NBG) candidates for RBG perovskite‐based tandem devices are very limited. Lead sulfide (PbS) colloidal quantum dots (CQDs) are a promising partner due to their broad absorption spectra. However, the efficiency of RBG perovskite/QD tandem devices still lags behind. Herein, efficient RBG perovskite/QDs four‐terminal tandem photovoltaics are successfully implemented through synergistic enhancement from transparent electrode and band alignment Engineering. For tin doped indium oxide (ITO) electrodes, their conductivity and near‐infrared transparency are leveraged using magnetron sputtering and reactive plasma deposition (RPD) methods. Furthermore, instead of traditional zinc oxide, aluminum‐doped zinc oxide (AZO) is developed to enhance the carrier extraction capability of PbS QD bottom cells. Based on the above enhancements, ≈0.95 eV PbS solar cells achieve a record efficiency of 14.14%. Integrated with the front semi‐transparent perovskite solar cells, the four‐terminal perovskite/QD tandem device reaches a record efficiency of 26.12%. The synergistic combination of the RBG perovskite and NBG QD devices provides promising prospects for tandem photovoltaics.

Structural and compositional gradients in alternating current sintered aluminum-doped zinc oxide

Flash sintering revitalizes the exploration of electric field and current effects on the microstructure with novel phenomena including rapid densification, low-temperature sintering, and unique microstructures. The aim of this study is to investigate the influence of electric current on the microstructural development of Al-doped ZnO (nAl=4at.%). We apply two sintering techniques, namely spark plasma sintering (SPS) and flash spark plasma sintering (FSPS), both conducted under identical conditions (AC, f=50Hz, |E→0|=25V/cm, p=180MPa) for three different temperatures 600∘C, 800∘C and 1000∘C. The distinguishing factor between the two techniques lies in the passage of electric current flow through the specimens in the case of FSPS. The resulting microstructures of the sintered pellets are examined by XRD, SEM, EDX, TEM and SAED to identify the process-related differences. While SPS specimens reveal a homogeneous microstructure, FSPS specimens exhibit a complex microstructure which consists of two distinct regions. The major volume of the FSPS pellets exhibits a structural gradient with coarse ZnO grains and ZnAl2O4 spinel precipitates in the center to fine ZnO grains at the periphery. This microstructure results from Joule heating and geometry-dependent heat dissipation, creating a symmetric temperature profile with a hot center. A minor volume of the FSPS specimens shows a gradient in microstructure and composition. Here, ZnAl2O4 spinel precipitates accumulate in the center and the periphery reveals Al-depleted, dense and very coarse grains. Electromigration of Al-cations and the thermodynamically favored formation of ZnAl2O4 in the hot center are proposed as underlying causes for the observed microstructure. The electric current in FSPS significantly alters the microstructure and composition of sintered specimen where dopant electromigration is most significant under high current densities above |J→|=29(5)A/cm2.

Effects of CCVD parameters on the growth of VACNT over AZO substrate

Both, aluminum doped zinc oxide (AZO) and vertically aligned carbon nanotubes (VACNT) have outstanding properties and promising applications in the future, however, there is little information in the scientific literature on whether this is feasible. In this study, we investigated the effects of catalyst layer deposition parameters and the synthesis parameters by using a simple and cost-effective dip coating method to form alumina support layer and iron and cobalt bimetal catalyst layer on the AZO surface thereafter performing synthesis via catalytic chemical vapor deposition technique at 650 °C.In order to gain useful information about the structure of the VACNTs, several parameters were varied during both catalyst layer preparation (e.g. catalyst ink concentration) and CCVD synthesis (e.g. water vapor gas feed, the presence of hydrogen gas). The resulting samples were investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results indicated that the length and structure of CNTs were strongly affected by the catalyst ink concentration and water vapor.

Investigation of Ethanol gas sensing properties of pristine and Al doped ZnO nanoparticles synthesized by Sol-gel method

Pure and Aluminum-doped Zinc Oxide nanoparticles were prepared by using a simple Sol–gel method. Al contents were varied with 1 wt% and 3 wt% at a fixed concentration of pure ZnO. Synthesized samples were calcinated at 400 °C for 2 h. The results of x-ray diffraction (XRD) confirm that the synthesized nanoparticles have a Hexagonal Wurtzite structure. The average crystallite size of the nanoparticles shows variation from 16 nm to 21 nm. Grain size and surface morphology were investigated with the help of a Field Emission Scanning Electron Microscope (FESEM). Functional groups present in the prepared samples were analyzed by using Fourier Transform Infra-red spectroscopy (FTIR). The percentage response of the fabricated sensor, containing Al-doped ZnO nanoparticles, was examined with exposure to the toxic gas Ethanol. It was observed that percentage response changes due to various sensing parameters like response time and percentage response which, were calculated at 100 ppm and 200 ppm concentrations of toxic Ethanol gas. It was found that with an increase in Al concentration as well as Ethanol ppm level the percentage response of synthesized samples is increased. The maximum percentage response of 17.82 and 20.91 at 100 and 200 ppm with 3 wt% of Al-doped ZnO nanoparticles was observed respectively, which is greater than that of pure ZnO. Also, the same sample shows the lowest response time of 215 s and 120 s at 100 ppm and 200 ppm, respectively. Thus, aluminum doping enhanced the gas sensing response of pristine zinc oxide nanoparticles.