ADVANCED SENSORS LABORATORY
Employing diverse fabrication techniques including Successive Ionic Layer Adsorption and Reaction (SILAR), Magnetron Sputtering, Electrospinning, Spin-coating, and Atomic Layer Deposition (ALD) etc., we seek to engineer novel sensor materials with tailored properties conducive to precise gas detection. By harnessing these advanced fabrication methodologies, we aim to enhance the performance and durability of gas sensors, thereby revolutionizing their application in environmental monitoring, industrial safety, and public health.
Through DFT and MD calculations, we probe the electronic structure and energetics of gas molecules adsorbed on sensor surfaces, providing valuable insights into the adsorption mechanisms, charge transfer processes, and surface reactivity. By accurately modeling the interactions between gas molecules and sensor materials at the atomic level, we aim to elucidate the factors governing sensor selectivity, sensitivity, and response kinetics.
Through systematic investigation and characterization at the nanoscale, we aspire to elucidate the fundamental mechanisms governing gas-surface interactions and sensor response dynamics. By gaining insights into the intricate interplay between nanostructure morphology, composition, and gas sensing performance, we aim to propel the development of next-generation gas sensor platforms capable of unprecedented sensitivity, selectivity, and reliability.
Furthermore, our research endeavors extend beyond fundamental understanding to practical implementation, with the ultimate goal of translating scientific discoveries into tangible technological solutions. By collaborating with industry partners and regulatory agencies, we strive to expedite the deployment of advanced gas sensor technologies for real-world applications, addressing pressing challenges related to air quality monitoring, emissions control, and workplace safety.
In summary, the Laboratory of Advanced Sensors is committed to pushing the boundaries of gas sensor innovation, leveraging interdisciplinary expertise in materials science, nanotechnology, and chemical engineering to engineer transformative solutions for a cleaner, safer, and healthier environment.
RESEARCH AREAS
1. Ultrasensitive MOS based gas sensors prepared by RF magnetron sputtering system
This study aimed to compare metal doping and magnetron sputtering with chemical-based methods for enhancing the surface and electrical characteristics of MOS films, particularly their gas sensing performance. RF magnetron sputtering was utilized to fabricate pure ZnO nanofilms as a reference and Ti-doped ZnO nanofilms with varying Ti concentrations. The doping process employed Ti-doped ZnO targets developed through solid-state reaction, with doping content determined via EDS analysis. All nanofilms exhibited a pure hexagonal wurtzite structure with uniform surfaces and nanoparticle distribution in Ti-doped samples. The observed improvements in film properties translated to enhanced gas sensor performance. Notably, the sensor with 1 wt% Ti content demonstrated superior sensitivity, stability, responsivity, reproducibility, and selectivity for NO gas detection, making it highly suitable for NO monitoring applications.
Find out more: Soltabayev B, Ajjaq A, Yergaliuly G, Kadyrov Y, Turlybekuly A, Acar S, Mentbayeva A. Ultrasensitive nitric oxide gas sensors based on Ti-doped ZnO nanofilms prepared by RF magnetron sputtering system. Journal of Alloys and Compounds. 2023 Aug 25;953:170125. https://doi.org/10.1016/j.jallcom.2023.170125
2. Optimization of Nanosized MOS's Gas Sensitivity Conditions by SILAR technique
Find out more: Yergaliuly, G., Soltabayev, B., Kalybekkyzy, S. et al. Effect of thickness and reaction media on properties of ZnO thin films by SILAR. Sci Rep 12, 851 (2022). https://doi.org/10.1038/s41598-022-04782-2
Find out more: Soltabayev B, Yergaliuly G, Ajjaq A, Beldeubayev A, Acar S, Bakenov Z, Mentbayeva A. ACS Appl. Mater. Interfaces 2022, 14, 36, 41555–41570 https://doi.org/10.1021/acsami.2c10055
4. Highly detective gas sensors based on heterostructured nano-films
This study represents a significant milestone as it is the first to employ a room-temperature N2O gas sensor capable of detecting ultra-low concentrations. The resulting gas sensors have outstanding sensitivity characteristics and can be used to develop commercial gas-sensing devices.
Find out more: Turlybekuly A, Sarsembina M, Mentbayeva A, Bakenov Z, Soltabayev B. CuO/TiO2 heterostructure-based sensors for conductometric NO2 and N2O gas detection at room temperature. Sensors and Actuators B: Chemical. 2023 https://doi.org/10.1016/j.snb.2023.134635
5. Optimization of Nanosized Metal Oxide Semiconductor (MOS) Conditions by Electrospinning Technique
The aim is to successfully optimize the synthesis parameters for nanoscale metal oxides using electrospinning, demonstrating precise control over particle size and morphology. By employing response surface methodology, key electrospinning and sintering conditions were systematically varied, resulting in the fabrication of minimal-sized ZnO nanoparticles with high crystallinity. The findings underscore the potential of electrospinning as a versatile technique for tailoring the properties of ZnO, offering promising prospects for its application in diverse microelectronic and optoelectronic devices, particularly in the development of advanced gas sensors and other semiconductor-based technologies.
Find out more: Rakhmanova, A.; Kalybekkyzy, S.; Soltabayev, B.; Bissenbay, A.; Kassenova, N.; Bakenov, Z.; Mentbayeva, A. Application of Response Surface Methodology for Optimization of Nanosized Zinc Oxide Synthesis Conditions by Electrospinning Technique. Nanomaterials 2022, 12, 1733. https://doi.org/10.3390/nano12101733
6. Fabrication of highly sensitive gas sensors by manipulating magnetron deposition parameters
CZO thin films (CZO-45W, CZO-60W, and CZO-75W) were successfully fabricated using RF magnetron technique on glass substrates, utilizing a cost-effective homemade target. XRD analysis confirmed a polycrystalline hexagonal wurtzite structure with preferential orientation towards the (002) plane. AFM measurements revealed differences in surface roughness, with CZO-60W having the highest RMS value. XPS analysis indicated the presence of oxygen vacancies, particularly pronounced in CZO-60W. Gas sensing tests across a range of CO2 concentrations showed CZO-60W sensor exhibited superior response and faster response time compared to CZO-45W. This enhanced performance is attributed to its higher surface roughness and the presence of defects, enabling greater CO2 adsorption capacity. Both sensors demonstrated a linear increase in response with increasing CO2 concentration up to 300 ppm, highlighting their potential for CO2 detection applications and the prospects for developing cost-effective and energy-efficient sensors.
Find out more: Soltabayev B, Raiymbekov Y, Nuftolla A, Turlybekuly A, Yergaliuly G, Mentbayeva A. Sensitivity Enhancement of CO2 Sensors at Room Temperature Based on the CZO Nanorod Architecture. ACS sensors. 2024 Feb 16. https://doi.org/10.1021/acssensors.3c02059
- Baktiyar Soltabayev, PhDLeading Reseacher and Lab Head
- Amanzhol Turlybekuly, PhDSenior Researcher
- Gani Yergaliuly, PhDResearcher
- Aizhan Rakhmanova, PhDResearcher
- Yernar ShynybekovResearcher Assistant
- Aidarbek Nuftolla
EQUIPMENT
The CTC-100 regulates and maintains a constant temperature within the system by controlling the power of the thermoelectric circuits, ensuring stable and accurate testing conditions.
Mass Flow Controllers (MFC-1,2):
These controllers manage and control the flow rates of gases through the system, allowing for precise adjustments to the gas mixtures being tested.
Humidity Control System:
An ultrasonic humidifier, along with a humidity power and control box, maintains the desired humidity levels in the chamber. A sensor continuously measures the humidity to ensure consistency.
Gas Test Chamber:
The chamber holds the gas being tested and enables accurate measurements to be taken. It is designed to provide a controlled environment for gas sensor testing.
Digital Interface Unit:
This unit communicates with the PC and facilitates the transfer of data between the gas measurement system and the computer, ensuring seamless data acquisition.
Gas Cylinders:
Cylinders holding dry air and target gases (CH4, NH3, CO, CO2, N2O, H2, ethanol, acetone, and toluol) provide the sources of gases for testing. Gases are added for 5-minute intervals, with a concentration range of 1-1500 ppm, to check the response of the gas sensor.
PC Control and Data Management:
The PC controls and manages the entire gas measurement system, receiving and storing data, and running analyses on the collected data. It ensures comprehensive monitoring and assessment of sensor performance.
This system is designed to test the response of gas sensors under controlled conditions, with target gases introduced for 5-minute periods (alternating 5 minutes of gas on and 5 minutes of gas off) to simulate real-world scenarios and assess sensor accuracy and reliability.
High Precision Measurements:
The HMS-5500 provides accurate and reliable measurements of Hall voltage, enabling precise determination of carrier concentration and mobility in semiconductor materials.
Versatile Material Compatibility:
Suitable for a wide range of materials, including semiconductors, metals, and thin films, allowing for diverse applications in material science and electronic engineering.
Automated Measurement Process:
The system features an automated measurement process, reducing user intervention and minimizing potential errors. This ensures consistent and reproducible results.
Temperature Control:
Equipped with temperature control capabilities, the HMS-5500 can perform measurements over a wide temperature range. This is crucial for understanding the temperature dependence of material properties.
Magnetic Field Application:
Utilizes a precise electromagnet to apply a controllable magnetic field, essential for conducting Hall effect measurements. The magnetic field strength can be adjusted to meet specific experimental requirements.
Precise Thin Film Deposition: Allows for controlled deposition of thin films with precise thickness and composition.
Versatile Material Compatibility: Suitable for a wide range of materials, including oxides, sulfides, and other compounds.
Layer-by-Layer Control: Enables atomic or molecular-level control over the film structure and properties.
Automated Process: Features automated dipping and rinsing cycles for consistent and reproducible results.
Scalability: Can be used for both small-scale research and large-scale industrial applications.
The SILAR Coating System is widely used in research and industry for applications such as photovoltaics, sensors, and optoelectronic devices, where precise thin film coatings are essential.