We report for the first time the thermoresistive property of p-type single crystalline 3C–SiC (p-3C–SiC), which was epitaxially grown on a silicon (Si) wafer, and then transferred to a glass ...substrate using a Focused Ion Beam (FIB) technique. A negative and relatively large temperature coefficient of resistance (TCR) up to −5500 ppm K −1 was observed. This TCR is attributed to two activation energy thresholds of 45 meV and 52 meV, corresponding to temperatures below and above 450 K, respectively, and a small reduction of hole mobility with increasing temperature. The large TCR indicates the suitability of p-3C–SiC for thermal-based sensors working in high-temperature environments.
The piezoresistive effect in silicon nanowires (SiNWs) has attracted a great deal of interest for NEMS devices. Most of the piezoresistive SiNWs reported in the literature were fabricated using the ...bottom up method or top down processes such as electron beam lithography (EBL). Focused ion beam (FIB), on the other hand, is more compatible with CMOS integration than the bottom up method, and is simpler and more capable of fabricating very narrow Si nanostructures compared to EBL and photolithography. Taking the advantages of FIB, this paper presents for the first time the piezoresistive effect of p-type SiNWs fabricated using focused ion beam implantation and wet etching. The SiNWs were locally amorphized by Ga
+
ion implantation, selectively wet-etched, and thermally annealed at 700 °C. A relatively large gauge factor of approximately 47 was found in the annealed SiNWs, indicating the potential of using the piezoresistive effect in top-down fabricated SiNWs for developing NEMS sensors.
This work reports the piezoresistance of silicon nanowires fabricated using focused ion beam and wet etching for NEMS mechanical sensors.
We report on the temperature dependence of the charge transport and activation energy of amorphous silicon carbide (a-SiC) thin films grown on quartz by low-pressure chemical vapor deposition. The ...electrical conductivity as characterized by the Arrhenius rule was found to vary distinctly under two activation energy thresholds of 150 and 205 meV, corresponding to temperature ranges of 300 to 450 K and 450 to 580 K, respectively. The a-SiC/quartz system displayed a high temperature coefficient of resistance ranging from −4,000 to −16,000 ppm/K, demonstrating a strong feasibility of using this material for highly sensitive thermal sensing applications.
This paper presents for the first time the effect of strain on the electrical conductance of p-type nanocrystalline SiC grown on a Si substrate. The gauge factor of the p-type nanocrystalline SiC was ...found to be 14.5 which is one order of magnitude larger than that in most metals. This result indicates that mechanical strain has a significant influence on the electrical conductance of p-type nanocrystalline SiC, which is promising for mechanical sensing applications in harsh environments.
A significant piezoresistive effect in p-type nanocrystalline SiC with a gauge factor of 14.5 was reported. This result indicates that p-type nanocrystalline SiC is a good candidate for MEMS sensors used in harsh environments and bio applications.
This article reports for the first time the electrical properties of fabricated n-3C-SiC/p-Si heterojunction diodes under external mechanical stress in the 110 direction. An anisotype heterojunction ...diode of n-3C-SiC/p-Si was fabricated by depositing 3C-SiC onto the Si substrate by low-pressure chemical vapor deposition. The mechanical stress significantly affected the scaling current density of the heterojunction. The scaling current density increases with stress and is explained in terms of a band offset reduction at the SiC/Si interface under applied stress. A reduction in the barrier height across the junction owing to applied stress is also explained quantitatively.
A cost effective and easy to fabricate stress sensor based on pseudo-Hall effect in Graphite on Paper (GOP) has been presented in this article. The four terminal devices were developed by pencil ...drawing with hand on to the paper substrate. The stress was applied to the paper containing four terminal devices with the input current applied at two terminals and the offset voltage observed at other two terminals called pseudo-Hall effect. The GOP stress sensor showed significant response to the applied stress which was smooth and linear. These results showed that the pseudo-Hall effect in GOP based four terminal devices can be used for cost effective, flexible and easy to make stress, strain or force sensors.
This paper presents for the first time the effect of strain on the electrical conductivity of p-type single crystalline 3C-SiC grown on a Si (111) substrate. 3C-SiC thin film was epitaxially formed ...on a Si (111) substrate using the low pressure chemical vapor deposition process. The piezoresistive effect of the grown film was investigated using the bending beam method. The average longitudinal gauge factor of the p-type single crystalline 3C-SiC was found to be around 11 and isotropic in the (111) plane. This gauge factor is 3 times smaller than that in a p-type 3C-SiC (100) plane. This reduction of the gauge factor was attributed to the high density of defects in the grown 3C-SiC (111) film. Nevertheless, the gauge factor of the p-type 3C-SiC (111) film is still approximately 5 times higher than that in most metals, indicating its potential for niche mechanical sensing applications.
This paper presents for the first time the effect of strain on the electrical conductivity of p-type single crystalline 3C-SiC grown on a Si (111) substrate.
This paper reports on the thermoresistive properties of graphite on paper (GOP). A negative temperature coefficient of resistance (TCR) from −2900 to −4400 ppm K −1 was observed for the GOP. This ...negative and large TCR is attributed to an increase in the thermionic emission current over a low potential barrier with increasing temperature. The potential barrier was found to be 33 meV between the graphite grains. The paper also demonstrates the use of the GOP in a highly sensitive (0.83 mV (m s −1 ) −0.8 mW −1 ) GOP-based anemometer, indicating strong feasibility of using this material for low-cost and sensitive thermal sensing applications.
In this work, structural and electrical properties of Y0.5Ca0.5MnO3 are investigated by employing X-ray diffraction and impedance spectroscopy, respectively. Applied ac electric field showed the ...charge ordering transition temperature around 265K and below this temperature the heteromorphic behavior of the sample is discussed in the proximity of TCO. With frequency effects the volume of robust charge orbital ordering (COO) domains diminishes due to different competing phases along with Jahn Teller distortions. Comprehensive melting and collapse of charge orbital ordering occurs below TN(125K), where a colossal drop in the value of impedance is observed. The change in profile of modulus plane plots determines the spreading of relaxation time of intermingled phases. Hopping mechanism is elaborated in terms of strong electron phonon coupling. Variable range hopping model and Arrhenius model are used to discuss the short and long range hopping between Mn3+ and Mn4+ channels assessing the activation energy Ea.
•Present study contains a detailed investigation over the electrical and structural properties of Y0.5Ca0.5MnO3 especially its behavior across the charge ordering transition.•Impedance measurements illustrate the comprehensive melting and collapse of robust charge orbital ordering with colossal drop in impedance.•In TN<T<TCO, Coulomb interactions give rise to Jahn–Teller distortions badly frustrating the spins of manganese.•Modulus plane plots determine the spreading of relaxation time of intermingled phases indicating the contribution of grain boundary and grain interior.•Variable range hopping model and Arrhenius model are used to discuss the short and long range hopping between Mn3+ and Mn4+ channels assessing the activation energy Ea.
•This article reports first results on pseudo-Hall effect in single crystal n-type 3C-SiC(100).•Impact of crystal orientation and direction of stress on this effect has been presented.•Single crystal ...n-type 3C-SiC(100) was grown by low pressure chemical vapor deposition.•Four-terminal devices were fabricated using the conventional MEMS process.•Highest value of pseudo-Hall effect up to date.
The pseudo-Hall effect in n-type single crystal 3C-SiC(100) with low carrier concentration has been investigated. Low pressure chemical vapor deposition was used to grow the single crystal n-type 3C-SiC(100) and Hall devices were fabricated by photolithography and dry etch processes. A large pseudo-Hall effect was observed in the grown thin films which showed a strong dependence on the crystallographic orientation. N-type 3C-SiC(100) with low carrier concentration shows a completely different behavior of pseudo-Hall measurements as compared to the p-type 3C-SiC(100). Contrary to p-type, the effect is maximum along 100 crystallographic orientation and minimum along 110 orientation. Moreover, the observed pseudo-Hall effect is 50% larger than p-type with higher carrier concentration grown by the same process which makes n-type 3C-SiC(100) with low carrier concentration more suitable material for designing highly sensitive micro-mechanical sensors.
PDF
