Large Temperature Coefficient Of Resistance Research Articles

On-Chip Modification of Titanium Electrothermal Characteristics by Joule Heating: Application to Terahertz Microbolometer.

This study demonstrates the conversion of metallic titanium (Ti) to titanium oxide just by conducting electrical current through Ti thin film in vacuum and increasing the temperature by Joule heating. This led to the improvement of electrical and thermal properties of a microbolometer. A microbolometer with an integrated Ti thermistor and heater width of 2.7 µm and a length of 50 µm was fabricated for the current study. Constant-voltage stresses were applied to the thermistor wire to observe the effect of the Joule heating on its properties. Thermistor resistance ~14 times the initial resistance was observed owing to the heating. A negative large temperature coefficient of resistance (TCR) of -0.32%/K was also observed owing to the treatment, leading to an improved responsivity of ~4.5 times from devices with untreated Ti thermistors. However, this does not improve the noise equivalent power (NEP), due to the increased flicker noise. Microstructural analyses with transmission electron microscopy (TEM), transmission electron diffraction (TED) and energy dispersive X-ray (EDX) confirm the formation of a titanium oxide (TiOx) semiconducting phase on the Ti phase (~85% purity) deposited initially, further to the heating. Formation of TiOx during annealing could minimize the narrow width effect, which we reported previously in thin metal wires, leading to enhancement of responsivity.

Large temperature coefficient of resistivity (TCR) of La0.67Ca0.33MnO3 polycrystalline ceramics improved by optimizing sintering temperatures

This work investigates fabrication of La0.67Ca0.33MnO3 (LCMO) polycrystalline ceramics using a facile sol–gel method at sintering temperatures (Ts) ranging from 1470 °C to 1540 °C and explores relationship between their electrical transport properties and Ts. X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoemission spectroscopy were employed to characterize crystal structure, morphologies, element distributions, and Mn3+/Mn4+ ratio of the as-obtained LCMO ceramics. The influence of Ts on phase purity, microstructure, morphology, and electrical transport properties was also investigated. LCMO ceramics exhibit increased grain size and higher temperature coefficient of resistivity (TCR) at higher temperatures. An increase in Ts can reduce the strength of electron–lattice interactions and theoretical Curie temperature in LCMO ceramic samples, which can in turn optimize their electrical transport properties. Moreover, an increase in Ts enhances double-exchange (DE) effect to some extent. The DE effect further affects resistivity and metal–insulator transition temperature of material. Additionally, small-polaron hopping model and phenomenological percolation model were used to characterize electrical transport in metal–insulator transition region. The temperature at which TCR is maximum (265.78 K) and the largest TCR value (58.16 %) were achieved at a Ts of 1530 °C. By modulating the sintering temperature, we achieved LCMO ceramics with larger grains and enhanced electrical properties. This optimization renders materials suitable for highly sensitive infrared bolometer applications.

High temperature coefficient of resistivity (TCR) of Nd0.67Sr0.33MnO3 films by optimizing sintering temperature

In this study, Nd0.67Sr0.33MnO3 (NSMO) films are deposited on La0.3Sr0.7Al0.65Ta0.35O3 (LSAT) substrates using sol–gel spin coating method and sintered at different temperatures (Ts = 1250, 1300, 1350, 1400 and 1450 °C). Consolidated analysis of their crystal structure, surface morphology and valence states enables one to conclude that increased Ts facilitates grain growth and enhances crystallinity of films. Moreover, enhancing Ts from 1250 to 1350 °C leads to a decrease in Mn-O bond length (d(Mn-O)) and an increase in Mn-O-Mn bond angle (θ(Mn-O-Mn)). In the XPS analysis, the Mn4+ and O2– content kept increasing with the rise of Ts. When Mn4+ concentration ≤ 33%, the double exchange (DE) interactions was undoubtedly facilitated, which was beneficial for the electrical properties of the NSMO films. These changes eventually result in large temperature coefficient of resistivity (TCR). According to these results, Nd0.67Sr0.33MnO3 film, with a maximum TCR value of 21.85% K−1 at Ts = 1350 °C, are promising materials for the manufacturing of sensitivity switches and infrared bolometers.

Optimized electrical transport properties of La0.7Ca0.18Sr0.12MnO3 film by adjusting sintering temperature

Perovskite manganites Lax(Ca1-ySry)1-xMnO3 have conspicuous electrical transport properties used for the application of uncooled bolometers. Thus, considerable attention has paid to the researches on electrical transport properties of Lax(Ca1-ySry)1-xMnO3. Temperature coefficient of resistivity (TCR) and the corresponding peak temperature (Tk) are crucial parameters for uncooled bolometers. Optimal La0.7Ca0.18Sr0.12MnO3 (LCSMO) films with highly oriented growth were prepared on (00l) LaAlO3 substrate at different sintering temperature (Ts) using a facile sol-gel spin coating method. Based on the analysis of microstructure, ionic valence, surface morphology and electrical transport properties, LCSMO films exhibit high crystallinity and large room-temperature TCR at higher Ts. Theoretical Curie temperature and the coupling of the electron lattice weaken gradually with the increase in Ts, which is the dominant factor for the optimization of electrical transport properties. Additionally, the results suggest that the active energy and theoretical Curie temperature play a crucial role in adjusting TCR and Tk. With the increase in Ts, the former increases while the latter decreased, resulting in a high TCR value (12.10%/K) at room temperature (297.38 K). The peak TCR value of LCSMO sintered at 1673 K is about 25% higher than that of the film sintered at 1473 K. The resulting LCSMO films demonstrate great potential for application in uncooled bolometers. Further theoretical basis on the effects of Ts on electrical transport properties was provided.

Co-optimization of Ag and K doping to regulate room-temperature coefficient of resistivity of La0.7Ag0.3-xKxMnO3 films

In this study, La0.7Ag0.3-xKxMnO3 (LAKMO, x = 0.15, 0.16, 0.17, 0.18, and 0.19) films with excellent electrical properties and low surface roughness were prepared on SrTiO3 (001) substrates using the spin-coating method. The crystal structures and ion valence states of the LAKMO films were modified by adjusting the doping amounts of Ag and K. The Jahn–Teller effect and electron–lattice coupling were enhanced with the MnO6 octahedron undergoes distortion. Moreover, the double-exchange interaction was improved with an increase in the number of Mn4+/Mn3+ ion pairs. Under the influence of these factors, the electrical transport properties especially the temperature coefficient of resistivity (TCR) of the LAKMO films can be refined modulated or optimized via A-site Ag and K co-doping. When x = 0.17, the maximum TCR of LAKMO reached 11.23 % K−1 at 293.23 K. Thus, La0.7Ag0.13K0.17MnO3 film with a large TCR exhibited excellent thermal properties at room temperature and was considered material for application to uncooled infrared bolometers.

Epitaxial Grown VO2 with Suppressed Hysteresis and Low Room Temperature Resistivity for High-Performance Thermal Sensor Applications

The ability of VO2 to undergo semiconductor-to-metal phase transition (SMT) upon heating makes it a very attractive material for uncooled bolometers. The SMT of VO2 represents a large temperature coefficient of resistance, which is an important parameter for the development of highly responsive microbolometers. However, other characteristics of the SMT of VO2 such as its high transition temperature (341.2 K), the sharpness of the transition, its hysteresis, and the high room temperature resistivity limit the performance of this material in microbolometers. In this work, we grow a high-quality epitaxial ultrathin film VO2 on c-plane Al2O3 by pulsed laser deposition. The low deposition temperature and tuning the oxygen partial pressure during the growth process enable control over the grain size and oxygen vacancy concentration. This allowed controlling the SMT parameters of the samples. In particular, we show that the high density of grain boundaries associated with nanosized grains suppresses the thermal hysteresis of the SMT. Simultaneous control over the density of oxygen vacancies and the size of grains enables the adjustment of the temperature coefficient of resistance, room temperature resistivity, SMT temperature, sharpness, and thermal hysteresis toward suitable values for the fabrication of efficient VO2-based uncooled bolometers. Compared with other VO2 fabrication methods, this approach can be viewed as a simpler alternative for VO2 fabrication with favorable properties for practical bolometer applications.

La0.7Ca0.3MnO3-δ:Ag nanocomposite thin films with large temperature coefficient of resistance (TCR)

In this work, oxygen vacancy-regulated La0.7Ca0.3MnO3-δ:Ag (LCMO:A) nanocomposite thin films on LaAlO3 (001) substrates were investigated to obtain films with large temperature coefficient of resistance (TCR) values. LCMO:A nanocomposite thin films were synthesized using pulsed laser deposition, and oxygen pressures during film deposition and annealing steps were optimized. As oxygen pressures increased, lattice parameter increased from 70 Pa to 100 Pa, Tp increased monotonically from 168 K to 282 K, and average Mn4+ concentration in the film increased as indicated by X-ray photoemission spectroscopy data. Record high TCR value of ∼37% K−1 was achieved in LCMO:A nanocomposite thin film prepared with optimal oxygen pressures, making this film promising candidate for applications in bolometers.

Highly Sensitive and Ultra-Broadband VO2(B) Photodetector Dominated by Bolometric Effect.

In this study, Wadsley B phase vanadium oxide (VO2(B)) with broad-band photoabsorption ability, a large temperature coefficient of resistance (TCR), and low noise was developed for uncooled broad-band detection. By using a freestanding structure and reducing the size of active area, the VO2(B) photodetector shows stable and excellent performances in the visible to the terahertz region (405 nm to 0.88 mm), with a peak TCR of -4.77% K-1 at 40 °C, a peak specific detectivity of 6.02 × 109 Jones, and a photoresponse time of 83 ms. A terahertz imaging ability with 30 × 30 pixels was demonstrated. Scanning photocurrent imaging and real-time temperature-photocurrent measurements confirm that a photothermal-type bolometric effect is the dominating mechanism. The study shows the potential of VO2(B) in applications as a new type of uncooled broad-band photodetection material and the potential to further raise the performance of broad-band photodetectors by structural design.

Large temperature coefficient of resistivity and magnetoresistance for polycrystalline La0.68Nd0.04Ca0.28MnO3 at low magnetic field

To obtain comprehensive materials with both high temperature coefficient of resistivity (TCR) and magnetoresistance (MR) at low magnetic fields, the polycrystalline La0.72−xNdxCa0.28MnO3(x = 0.02, 0.04, 0.06, and 0.08) were synthesized using the sol–gel method, which is a significant practical application in magnetic sensors and bolometers. We observe an enhancement of TCR and MR by substituting La3+ with Nd3+. The excellent TCR (19.21%·K−1) and MR (73.10%) are observed in La0.68Nd0.04Ca0.28MnO3 at the 1 T magnetic field. Meanwhile, the maximum TCR reaches 22.68%·K−1 without a magnetic field. This substitution increased the total magnetic moment and a slight increase in average grain size. The Mn3+ and Nd3+ spin within the disordered region realign along the field direction with a magnetic field. Therefore, Nd-doped La0.72Ca0.28MnO3 ceramic materials can effectively improve the material properties.

Large temperature coefficient of resistivity (TCR) of La1-xCaxMnO3 films prepared by spin-coating method

La1-xAxMnO3 (A = alkaline-earth or alkali metal) perovskites with large temperature coefficient of resistivity (TCR) offer immense opportunity for the application in high-performance infrared bolometer. However, numerous studies have revealed that the manganite films with large TCR values are not easily obtained by various fabrication technologies. Herein, a facile sol-gel spin-coating technique was used to prepare La1-xCaxMnO3 (LCMO, 0.280 ≤ x ≤ 0.375) films. All the samples were highly oriented along the out-of-plane direction of La0.3Sr0.7Al0.65Ta0.35O3 (001) substrates. With the rise in Ca doping amount, the resistivity of the films first decreased, and then, increased. This change can be attributed to the competition between the carrier concentration and lattice distortion. The LCMO films displayed large TCR and low-field magnetoresistance (MR) values, which exceeded those of previously reported thin films. The maximum TCR and low-field MR values were observed at x = 0.330, reaching 30.13% K−1 (266.43 K) and 68.6% (270.08 K), respectively. The La0.67Ca0.33MnO3 film with large TCR and MR values presents potential for the applications in high-sensitivity infrared bolometers and magnetic sensors.

Large temperature coefficient of resistance and magnetoresistance of La0.71Ca0.29Mn1-xCoxO3 polycrystalline ceramics

La0.71Ca0.29MnO3 is a strongly correlated electronic material, which has been extensively researched and has high application value. It is known that improvements of the temperature coefficient of resistance (TCR) and magnetoresistance (MR), which are important parameters for the application of such materials, promote their applications. Using other elements to replace Mn sites is one of the methods to improve the specific properties. Herein, we prepare a series of La0.71Ca0.29Mn1-xCoxO3 (x = 0, 0.01, 0.03, 0.05, 0.1) polycrystalline ceramics via sol-gel method, and explore the effect of Co doping on the properties of La0.71Ca0.29MnO3. The results show that a small amount of Co doping can significantly improve TCR and MR. Under our excellent preparation process, TCR of La0.71Ca0.29MnO3 was 22.5%·K−1 and MR was 52.9% (under 1T magnetic field). When Co doping is 0.01, TCR reaches 35.1%·K−1 value and MR reaches 64.8%. This can provide critical information for the future application of such materials in bolometers and magnetic sensors.

Synthesis and characterization of vanadium and iron tellurite glasses for applications as thermal sensors

Semiconducting transition metal oxide tellurite glasses: xV2O5-(100-x)TeO2 (x = 10, 30, 40, 50 and 55, 60, 65 and 70 mol%), xCuO-50V2O5-(50-x)TeO2 (x = 1, 3 and 5 mol%), xFe2O3-(100-x)TeO2 (x = 10 and 20 mol%) and xFe2O3–45V2O5-(55-x)TeO2 (x = 5 and 10 mol%) were prepared by normal and splat quenching techniques. The thermal, electrical and structural properties of glasses were characterized. The highest electronic conduction is in the xV2O5-(100-x)TeO2 glasses; the room temperature conductivity of this glass series increases from 9.21 × 10−9 Ω−1m−1 to 3.30 × 10−4 Ω−1m−1 upon increasing V2O5 concentration from 10 to 70 mol%. Iron tellurite glasses also show a large enhancement of conductivity with an increase in Fe2O3 concentration. The glass transition temperature (Tg) of vanadium tellurite glasses decreases, while those of iron tellurite glasses increases with an increase in V2O5 and Fe2O3 concentrations respectively. The incorporation of Cu and Fe ions in xV2O5-(100-x)TeO2 increases Tg significantly but it suppresses the electrical conductivity. Vanadium tellurite glasses show the growth of α-TeO2 crystals in the glass matrix on irradiation with 488 nm Ar ion laser. Transition metal oxide tellurite glasses have potential application as thermal and body temperature sensors due to their large temperature coefficient of resistance in the range of −3.04 to −2.26% K−1.

Effect of sintering temperature on structural and electrical transport properties of La0.7Ca0.28K0.02MnO3 ceramics

Manganites with large temperature coefficient of resistance (TCR) have been considered as potential candidate for infrared detecting. To date, A-site doping with alkaline-earth metal (+2 oxidation state) has been widely used to improve the TCR. However, doping with alkali ions (+1 oxidation state) was less explored. In this study, 2% K doped La0.7Ca0.28K0.02MnO3 (LCKMO) ceramics were prepared by sol-gel method and sintered within the temperature range of 1000–1300 °C for structural and electrical transport properties investigation. X-ray diffraction (XRD) analysis demonstrated that all samples exhibited an orthorhombic perovskite structure with space group Pnma. Elevated sintering temperature would lead to an increase in grain size, which could account for the concurrent decrease of the resistivity (ρ). By optimizing the sintering process, the magnetoresistance (MR) and TCR reached their maxima of 60.95% and 13.54% K−1, respectively, for sintering temperature of 1200 °C. By fitting the temperature dependence of resistivity (ρ-T), grain boundary scattering and small-polaron hopping (SPH) were found to dominate in the low-temperature ferromagnetic and high-temperature paramagnetic regions, respectively. In addition, the ρ-T in the whole temperature range of 100–300 K can also be explained by the percolation model.

Large temperature coefficient of resistance in atomically thin two-dimensional semiconductors

The temperature coefficient of resistance (TCR) of thin metal lines is often used for applications in thermometry, bolometers, or thermal accelerometers. However, metal TCR is much degraded in nanometer-thin films due to strong surface scattering, preventing their use as fast thermal sensors, which simultaneously require low thermal mass and large TCR. In contrast, here we show that the TCR of doped two-dimensional (2D) semiconductors is large (∼0.3% K−1 at 300 K in MoS2 and MoTe2) even at sub-nanometer thickness. This is larger than that of any metals with thicknesses up to ∼35 nm and larger than that of ∼95 nm thick Cu lines (0.25% K−1) at 300 K. At 100 K, the TCR of these 2D materials is doubled, ∼0.6% K−1. Comparison with detailed 2D transport models suggests that the TCR could be further enhanced (up to 0.45% K−1 at 300 K and ∼2.5% K−1 at 100 K) by reducing the density of Coulomb impurities and scattering centers. Such high TCR in atomically thin 2D semiconductors could lead to the design of fast thermal sensors.

(Pr0.75La0.25)0.7Sr0.3MnO3:Agx (0 ≤ x ≤ 0.25) polycrystalline ceramics with room-temperature TCR improvement for uncooled infrared bolometers

In this work, perovskite manganite (Pr0.75La0.25)0.7Sr0.3MnO3:Agx (PLSMO:Agx, x = 0, 0.05, 0.10, 0.15, 0.20 and 0.25) ceramics were successfully prepared by sol-gel route and solid-state reaction. The surface morphologies, peak temperature variation behaviors of temperature coefficient of resistivity (TCR), microstructural and electrical transport properties of all the specimens were analyzed by various testing methods like XRD, SEM, EDS, R-T and XPS. XRD Rietveld refinement data demonstrated that Mn–O bond length, Mn–O–Mn bond angles and the unit cell volume increased along with the rise in x. Consequently, the bandwidth describing the overlap between the O2p and Mn3d orbitals reduced, and this change further affected the electrical transport properties. Scanning electron microscopy (SEM) images indicated that silver was helpful in increasing the grain size. The metal-insulator transition temperature increased due to the enhancement in double exchange (DE) interaction. X-ray photoelectron spectroscopy (XPS) fitting data (percentage of Mn4+ and O2−) along with XRD Rietveld refinement data confirmed the enhancement in DE interaction. The most remarkable thing was that the reduction in resistivity occurred gradually, which resulted in a significant improvement in the TCR. The TCR value achieved 11.35% K−1 with the peak temperature being 300.69 K (room-temperature ~ 300 K) at x = 0.15. Obviously, obtaining a large room-temperature TCR value (≥10% K−1) in praseodymium perovskite oxides was encouraging since such results have not been explored previously. Overall, the proposed PLSMO:Ag0.15 ceramic with large room-temperature TCR value look prospective candidates for future advanced uncooled infrared bolometers.

La0·7Ca0.3−xSrxMnO3:Ag0.2 (0.0165 ≤ x ≤ 0.1) ceramics with large and stable TCR in different magnetic field environments

La0·7Ca0.3−xSrxMnO3:Ag0.2 (LCSMO:Ag) ceramics with varying strontium (Sr) content (x = 0.0165, 0.03, 0.05, 0.07, and 0.1) were synthesized using a combination of sol–gel and solid-state doping methods and studied as colossal magnetoresistance materials. Significant improvements in the peak temperature coefficient of resistivity (TCR) and resistivity (ρ) were observed across all ceramic samples when the mol% of Sr was adjusted. The low ρ and large TCR values resulted from a combination of two factors. First, the presence of Sr led to the increase in the grain size and decrease in the number of boundaries, which improved the electrical transport and reduced the boundary scattering effects. This resulted in additional improvement in the grain arrangement order. Second, the cell volume (Vcell) and octahedron volume (Voct) both decreased first and then increased. The MnO6 octahedron underwent gradual deformation into a flattened shape, which facilitated carrier migration and increased electrical sensitivity of the material. The ceramic with x = 0.03 maintained high and stable TCR values in different working environments, both without a magnetic field (TCRo, 54.76% K−1) and in the presence of a vertical field (TCR⊥, 33.33% K−1). Furthermore, the material exhibited a low resistivity and a higher insulator–metal transition temperature (Tp). Performance differences among the samples were comprehensively and systematically explained by conducting cross magnetic field tests with field directions parallel and perpendicular to the flat surface of the bulk material, respectively. Overall, the findings of this study indicate that these ceramics act as promising candidates for future applications in information storage devices and magnetic sensors.

Electrical conduction in La0.85Sr0.15MnO3:Agx (0 ≤ x ≤ 0.5) ceramics with large room-temperature TCR

Polycrystalline La0.85Sr0.15MnO3:Agx (LSMO:Agx, 0 ≤ x ≤ 0.5) ceramics were synthesized using sol-gel procedure. All specimens showed rhombohedral perovskite structures in R3‾c space group. As the amount of Ag increased, grain size of ceramics increased, and resistivity accordingly decreased. Large temperature coefficient of resistivity (TCR) of 22.9% K−1 was obtained at room temperature (289.2 K) for x = 0.4. Interestingly, analyses of resistivity-temperature (ρ-T) experimental data showed that conduction mechanism over entire temperature region perfectly matched theoretical percolation model. This reveals that electrical transport properties of LSMO:Agx ceramics are mainly affected by domains, grain boundaries (GBs), and Kondo-like spin-dependent scattering. It also demonstrates the coexistence of paramagnetic (FM) and ferromagnetic (PM) phases in LSMO:Agx ceramics. The ρ-T and scanning electron microscopy (SEM) results confirmed that the introduction of Ag weakened these scattering effects.

Room-temperature TCR and low-field MR of La0.7Ca0.3-xSrxMnO3 (0.06 ≤ x ≤ 0.1) polycrystalline ceramics

In this study, La0.7Ca0.3-xSrxMnO3 (LCSMO, 0.06 ≤ x ≤ 0.1) ceramics were synthesized via a sol-gel method. The perovskite microstructure, electrical transport properties, low-field magnetoresistance (MR) and peak temperature coefficient of resistivity (TCR) behaviors of the as-obtained materials were all studied and the results were discussed. Grain size of LCSMO ceramics expanded as more Sr was added but grain boundaries (GBs) decreased. Field emission scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS) and vibrating sample magnetometry (VSM) analyses suggested that addition of Sr greatly enhanced the electrical/magnetic properties of the prepared specimens. The metal-insulator transition temperature rose as doping concentration x enhanced, and increased Ca2+ substitution led to reduced peaks of MR and TCR. For single-phase LCSMO, large room-temperature TCR and low-field MR effects (0.8 T magnetic field) were obtained by controlling the level of Sr2+ substituted Ca2+. For x = 0.095, the optimized room-temperature TCR and MR reached 13.78% K−1 (299.2 K) and 26.41% (302.6 K), respectively. Overall, LCSMO ceramics have broad application prospects in photoelectronic or magnetic devices at room-temperature.

La0.67(Ca0.24Sr0.09)MnO3:xAg2O (0 ≤ x ≤ 0.25) composites with improved room–temperature TCR and MR for advanced uncooling infrared bolometers and magnetic sensors

In this research, high–density La0.67(Ca0.24Sr0.09)MnO3:xAg2O (LCSMO: xAg2O, x = 0, 0.05, 0.1. 0.15, 0.2, and 0.25) composites were successfully fabricated through the conventional sol-gel method. Scanning electron microscopy (SEM), X–ray photoelectron spectroscopy (XPS) and XRD data confirmed presence of silver at A sites (La3+/Ca2+/Sr2+) as Ag+ and segregates at grain boundaries (GBs) to form metallic silver. The electrical properties greatly improved by adding Ag2O. Significant enhancements in peak temperature coefficient of resistivity (TCR) and magnetoresistance (MR) at room–temperature (300 K) were observed for LCSMO:xAg2O composites. The peak TCR increased from 3.7% K−1 (299.3 K, for x = 0) to 14.8% K−1 (301.0 K, for x = 0.2), and MR rose from 16.9% (303.0 K, for x = 0) to 34.1% (300.6 K, for x = 0.2). These improvements in peak TCR were attributed to increased grain size and formation of metallic silver at GBs or within the composites. Moreover, peak MR was higher in Ag2O doped composites, which was mainly due to large spin polarization effect and strong coupling ferromagnetic domains under external magnetic field. Overall, the large room-temperature TCR and MR values of LCSMO:0.2Ag2O composites look promising for future advanced uncooling infrared bolometers and magnetic sensors.

Discrimination of VOCs molecules via extracting concealed features from a temperature-modulated p-type NiO sensor

Poor selectivity of metal oxide semiconductor (MOS) gas sensors (toward volatile organic compounds, VOCs) poses a significant challenge for their applications in the emerging areas of personal health and air quality monitoring. Extensive efforts have been devoted to improving the selectivity of gas sensors via extracting features from their electrical response signals. Alternative to the conventional strategy of enlarging the number of sensor arrays, analyzing the transient signal of a temperature modulated gas sensor provides an efficient approach to extract molecule features. Despite p-type MOS outperforms n-type counterpart in terms of (photo)catalytic properties, further exploration on thermal modulation of p-type MOS sensor has been scarcely reported. In this work, p-type NiO nanoparticles with grain size of 17.4 ± 4.0 nm have been synthesized with the assistance of bacterial cellulose (BC) scaffold. Transient response characteristics of NiO sensor (modulated by a staircase waveform) toward 5 kinds of VOCs have been investigated. The removals of irrelevant electrical signals, particularly induced by large temperature coefficient of resistance (TCR) of p-NiO, allows us to extract the intrinsic features of tested VOCs molecules by discrete wavelet transform (DWT). Successful classification and recognition of tested VOCs molecules, including three kinds of benzene series (benzene, toluene and chlorobenzene), have been achieved by typically non-selective p-type NiO sensor with a low sensitivity. Our work highlights that eliminating the irrelevant thermally modulated electric signals is essential for expanding the recognition capability of a single MOS sensor (toward VOCs molecules), and sheds light on the exploring future smart gas molecule recognition chips.