Alireza Tari - Academia.edu (original) (raw)

Papers by Alireza Tari

Research paper thumbnail of Selective wet-etch processing of optically transparent flexible InGaZnO thin-film transistors

Applied Physics Letters, 2015

Research paper thumbnail of Low-Power Bootstrapped Rail-to-Rail Logic Gates for Thin Film Applications

Journal of Display Technology, 2016

Research paper thumbnail of The effect of different content of Al, RE and Si element on the microstructure, mechanical and creep properties of Mg–Al alloys

Materials Science Engineering a Structural Materials Properties Microstructure and Processing, Oct 15, 2009

The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE ... more The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE alloys was investigated in this study. The steady state creep rates were specified and it was found that the creep behavior of the alloy, which is dependent on the stability of the near grain boundary microstructure, was improved by the RE and Si addition. For the AZ91 alloy, the results indicate a mixed mode of creep behavior, with some grain boundary effects contributing to the overall behavior. However for the RE and Si added samples, sliding of grain boundaries was greatly suppressed and the dislocation climb controlled creep was the dominant deformation mechanism. Analysis of creep rates also showed that the Si addition resulted in formation of Mg 2 Si particles (in Chinese Script form) which have a high thermal stability. After Si addition the steady state creep rates were decreased and the creep resistance was improved. This was due to formation of Mg 2 Si particles which change the deformation mechanism at elevated temperatures. Addition of cerium rich misch metal to AZ91 alloy resulted in formation of needle shape particles, which also had a very high thermal stability, providing increased creep resistance and superior mechanical properties compared to AZ91 magnesium alloy. As a result, the grain boundaries were less susceptible for grain boundary sliding at high temperatures. By decreasing the Al content of the alloy having 2 wt.% RE from 9 to 4 wt.%, the steady state creep rate was also decreased compared to AZ91 + 2% RE alloy. The fracture mechanism was also investigated and it was observed that although the Si addition improves the creep resistance, it can make the alloy brittle at ambient temperature.

Research paper thumbnail of Electrical dependence on the chemical composition of the gate dielectric in indium gallium zinc oxide thin-film transistors

Applied Physics Letters, 2015

Research paper thumbnail of Effect of deep cryogenic treatment on microstructure, creep and wear behaviors of AZ91 magnesium alloy

Materials Science and Engineering: A, 2009

This paper focuses on the effect of deep cryogenic treatment (−196°C) on microstructure and mecha... more This paper focuses on the effect of deep cryogenic treatment (−196°C) on microstructure and mechanical properties of AZ91 magnesium alloy. The execution of deep cryogenic treatment on samples changed the distribution of β precipitates. The tiny laminar β particles almost dissolved in the microstructure and the coarse divorced eutectic β phase penetrated into the matrix. This microstructural modification resulted in

Research paper thumbnail of The effect of different content of Al, RE and Si element on the microstructure, mechanical and creep properties of Mg–Al alloys

Materials Science and Engineering: A, 2009

The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE ... more The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE alloys was investigated in this study. The steady state creep rates were specified and it was found that the creep behavior of the alloy, which is dependent on the stability of the near grain boundary microstructure, was improved by the RE and Si addition. For the AZ91 alloy, the results indicate a mixed mode of creep behavior, with some grain boundary effects contributing to the overall behavior. However for the RE and Si added samples, sliding of grain boundaries was greatly suppressed and the dislocation climb controlled creep was the dominant deformation mechanism. Analysis of creep rates also showed that the Si addition resulted in formation of Mg 2 Si particles (in Chinese Script form) which have a high thermal stability. After Si addition the steady state creep rates were decreased and the creep resistance was improved. This was due to formation of Mg 2 Si particles which change the deformation mechanism at elevated temperatures. Addition of cerium rich misch metal to AZ91 alloy resulted in formation of needle shape particles, which also had a very high thermal stability, providing increased creep resistance and superior mechanical properties compared to AZ91 magnesium alloy. As a result, the grain boundaries were less susceptible for grain boundary sliding at high temperatures. By decreasing the Al content of the alloy having 2 wt.% RE from 9 to 4 wt.%, the steady state creep rate was also decreased compared to AZ91 + 2% RE alloy. The fracture mechanism was also investigated and it was observed that although the Si addition improves the creep resistance, it can make the alloy brittle at ambient temperature.

Research paper thumbnail of Enhanced Dark Current Suppression of Amorphous Selenium Detector With Use of IGZO Hole Blocking Layer

IEEE Transactions on Electron Devices, 2014

ABSTRACT We examined the potential application of indium gallium zinc oxide (IGZO) as a hole-bloc... more ABSTRACT We examined the potential application of indium gallium zinc oxide (IGZO) as a hole-blocking layer for an amorphous selenium (a-Se)-based detector to reduce the dark current and improve the sensitivity of the detector. By employing a thin layer of IGZO (375 nm), the dark current of an a-Se detector remains below 1 pA/mm (^{2}) up to electric fields as high as 60 V/ (mu ) m. The measured dark current at different electric fields is comparable to the thermal generation currents in a-Se, thus demonstrating the good hole-blocking properties of IGZO. The detector’s photo response was characterized using a blue light-emitting diode at different electric fields. A factor of three improvement in external quantum efficiency was observed by increasing the electric field of the detector from 10 to 50 V/ (mu ) m.

Research paper thumbnail of Selective wet-etch processing of optically transparent flexible InGaZnO thin-film transistors

Applied Physics Letters, 2015

Research paper thumbnail of Low-Power Bootstrapped Rail-to-Rail Logic Gates for Thin Film Applications

Journal of Display Technology, 2016

Research paper thumbnail of The effect of different content of Al, RE and Si element on the microstructure, mechanical and creep properties of Mg–Al alloys

Materials Science Engineering a Structural Materials Properties Microstructure and Processing, Oct 15, 2009

The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE ... more The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE alloys was investigated in this study. The steady state creep rates were specified and it was found that the creep behavior of the alloy, which is dependent on the stability of the near grain boundary microstructure, was improved by the RE and Si addition. For the AZ91 alloy, the results indicate a mixed mode of creep behavior, with some grain boundary effects contributing to the overall behavior. However for the RE and Si added samples, sliding of grain boundaries was greatly suppressed and the dislocation climb controlled creep was the dominant deformation mechanism. Analysis of creep rates also showed that the Si addition resulted in formation of Mg 2 Si particles (in Chinese Script form) which have a high thermal stability. After Si addition the steady state creep rates were decreased and the creep resistance was improved. This was due to formation of Mg 2 Si particles which change the deformation mechanism at elevated temperatures. Addition of cerium rich misch metal to AZ91 alloy resulted in formation of needle shape particles, which also had a very high thermal stability, providing increased creep resistance and superior mechanical properties compared to AZ91 magnesium alloy. As a result, the grain boundaries were less susceptible for grain boundary sliding at high temperatures. By decreasing the Al content of the alloy having 2 wt.% RE from 9 to 4 wt.%, the steady state creep rate was also decreased compared to AZ91 + 2% RE alloy. The fracture mechanism was also investigated and it was observed that although the Si addition improves the creep resistance, it can make the alloy brittle at ambient temperature.

Research paper thumbnail of Electrical dependence on the chemical composition of the gate dielectric in indium gallium zinc oxide thin-film transistors

Applied Physics Letters, 2015

Research paper thumbnail of Effect of deep cryogenic treatment on microstructure, creep and wear behaviors of AZ91 magnesium alloy

Materials Science and Engineering: A, 2009

This paper focuses on the effect of deep cryogenic treatment (−196°C) on microstructure and mecha... more This paper focuses on the effect of deep cryogenic treatment (−196°C) on microstructure and mechanical properties of AZ91 magnesium alloy. The execution of deep cryogenic treatment on samples changed the distribution of β precipitates. The tiny laminar β particles almost dissolved in the microstructure and the coarse divorced eutectic β phase penetrated into the matrix. This microstructural modification resulted in

Research paper thumbnail of The effect of different content of Al, RE and Si element on the microstructure, mechanical and creep properties of Mg–Al alloys

Materials Science and Engineering: A, 2009

The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE ... more The effect of Al content and Si addition on the microstructural and creep properties of Mg-Al-RE alloys was investigated in this study. The steady state creep rates were specified and it was found that the creep behavior of the alloy, which is dependent on the stability of the near grain boundary microstructure, was improved by the RE and Si addition. For the AZ91 alloy, the results indicate a mixed mode of creep behavior, with some grain boundary effects contributing to the overall behavior. However for the RE and Si added samples, sliding of grain boundaries was greatly suppressed and the dislocation climb controlled creep was the dominant deformation mechanism. Analysis of creep rates also showed that the Si addition resulted in formation of Mg 2 Si particles (in Chinese Script form) which have a high thermal stability. After Si addition the steady state creep rates were decreased and the creep resistance was improved. This was due to formation of Mg 2 Si particles which change the deformation mechanism at elevated temperatures. Addition of cerium rich misch metal to AZ91 alloy resulted in formation of needle shape particles, which also had a very high thermal stability, providing increased creep resistance and superior mechanical properties compared to AZ91 magnesium alloy. As a result, the grain boundaries were less susceptible for grain boundary sliding at high temperatures. By decreasing the Al content of the alloy having 2 wt.% RE from 9 to 4 wt.%, the steady state creep rate was also decreased compared to AZ91 + 2% RE alloy. The fracture mechanism was also investigated and it was observed that although the Si addition improves the creep resistance, it can make the alloy brittle at ambient temperature.

Research paper thumbnail of Enhanced Dark Current Suppression of Amorphous Selenium Detector With Use of IGZO Hole Blocking Layer

IEEE Transactions on Electron Devices, 2014

ABSTRACT We examined the potential application of indium gallium zinc oxide (IGZO) as a hole-bloc... more ABSTRACT We examined the potential application of indium gallium zinc oxide (IGZO) as a hole-blocking layer for an amorphous selenium (a-Se)-based detector to reduce the dark current and improve the sensitivity of the detector. By employing a thin layer of IGZO (375 nm), the dark current of an a-Se detector remains below 1 pA/mm (^{2}) up to electric fields as high as 60 V/ (mu ) m. The measured dark current at different electric fields is comparable to the thermal generation currents in a-Se, thus demonstrating the good hole-blocking properties of IGZO. The detector’s photo response was characterized using a blue light-emitting diode at different electric fields. A factor of three improvement in external quantum efficiency was observed by increasing the electric field of the detector from 10 to 50 V/ (mu ) m.