Strain gauges of GaSbFeGa1.3 eutectic composites

Abstract

A needle-shaped metallic FeGa 1.3 phase oriented in a specific direction and uniformly distributed within a GaSb matrix was grown by a vertical Bridgman method. Strain-gauge characteristics, such as strain-sensitivity coefficient (S), temperature coefficient of strain sensitivity (TCS) and temperature coefficient of resistance, of GaSb and GaSb-FeGa 1.3 eutectic alloy have been investigated in the range of 200 to 400 K under deformation up to strains of 1.3 × 10 −3 . The value of S of the GaSb-FeGa 1.3 composition is measured to be 40 ± 5 and its TCS is about 0.2 % deg −1 when the current is perpendicular to the needles and the needles are parallel to the plane of the gauge substrate. The strain-sensitivity characteristics are linear and hysteresis free in the investigated temperature range in the aforementioned direction. It was found that GaSb-FeGa 1.3 -based strain gauges possess better deformation characteristics than GaSb-based gauges. Semiconductor resistance strain gauges, which convert a mechanical stimulus into an electrical signal, are widely used in measuring stresses and strains in many components such as structural elements, machine parts and mechanical test samples [1,2]. Ge-, Si-and Ge-Si-based strain gauges have been widely utilized and their properties have been investigated [3][4][5]. However, these semiconductor sensors exhibit a high resistivity and a high strain-sensitivity coefficient as a function of temperature. Also, there is a nonlinear behavior with strain. These factors cause a number of difficulties in modeling and designing strain-gauge-type devices. Therefore, the investigation of potential semiconductor materials to be used as mechanical sensors with thermostable parameters is essential.GaSb is a candidate semiconductor for the exploration of its strain effect due to its interesting band structure [6,7]. Although the sensors based on GaSb show a large strainsensitivity coefficient, they exhibit a significant temperature dependence of resistivity and strain-sensitivity coefficient. Interestingly, the incorporation of FeGa 1.3 metallic phase in u Fax: +994-1239-59-61, E-mail: rashad@physics.ab.az the GaSb matrix causes distinctive features of the straingauge characteristics in this material. Such heterogeneous structures possess the system of a semiconductor-metal type of GaSb-FeGa alloy. In our previous study [8], microstructure, electrical and thermal properties of GaSb-FeGa 1.3 eutectic composition were revealed and features of electron and phonon processes were studied. In these systems, it is considered that the electrical resistivity of the semiconductormetal boundaries is affected by the amount of the deformation on the alloy. Also, by forming eutectic alloys, the interactions between atoms are weakened and the bond energy of valance electrons that is related to the essential redistribution of charge electron densities of the nearby atoms of all components on these boundaries diminishes. This may have some considerable effect on the strain-gauge characteristics of th...

Thermostable tensoresistors of Co doped GaSb–FeGa1.3 eutectic composites

“…This tensoresistor on the base of GaSb-FeGa 1.3 Co composite was attached to the bending beam (as illustrated in Fig. 1) using VL-931 glue as described in a previous work [1]. Characterization of the strain gauge was carried out using the compensation method in the range of 200-400 K and with deformation up to 2 × 10 −3 rel.…”

“…unit. The measurements were performed with the current (I) perpendicular to the needles (x) and the needles parallel to the plane (P) of the gauge substrate (I ⊥ x P), owing to the strain gauges that exhibit the greatest strain sensitivity coefficient (S) [1]. The relative deformation of the bending beams (ε) was determined based on the following equation:…”

“…In previous studies [1], we showed that tensoresistors based on GaSb-FeGa 1.3 eutectic composites have thermostable deformation characteristics that are related to the deep impurity levels of iron atoms that are formed in the band gap of the GaSb matrix. It is expected that GaSb-FeGa 1.3 eutectic composites doped with Co atoms will create additional deep levels in the matrix that will result in higher stability of the strain characteristics as a function of temperature.…”

“…In previous studies, we showed that these properties can be improved by fabrication of strain gauges using semiconductor-metal eutectic composites [1]. The advantages of such composites is that the properties of semiconductors and metals combine, allowing for the ability to control their characteristics with electric and magnetic fields, temperature, pressure, and various types of impurities.…”

“…Within the microstructure of semiconductor-metal eutectic composites, the metal phase exists as needle-shaped inclusions that reduce the brittleness of the material and cause distinctive behavior in electron and phonon processes in addition to changing the deformation characteristics [1,2]. Some characteristics of the composites may be adjustable by varying the size and density of the metallic inclusions.…”