Síntesis y caracterización por difracción de rayos X de películas de SnO2:Cu: Estudio en la detección de vapor de etanol
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Date
2024
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Universidad Nacional de Trujillo
Abstract
En el presente trabajo se estudió el Efecto de la concentración de Cu en películas delgadas de dióxido de estaño (SnO2) sobre su Sensibilidad en la detección de vapor de etanol. Estas películas fueron depositadas sobre retazos de obleas de silicio-platino (Si/Pt) a temperatura de síntesis de 400°C mediante la técnica de rociado pirolítico. En este trabajo se empleó la técnica de difracción de rayos X por cristales, verificando la presencia de una estructura característica tipo casiterita propia del SnO2; así como la presencia de impurezas de Cu debido al dopante en las películas. Las imágenes de microscopia electrónica de barrido (MEB) y de microscopia de fuerza atómica (AFM) revelaron un cambio en la forma de los granos tornándose triangulares por la presencia del Cu, también mostraron un incremento en la rugosidad superficial. Los espectros de infrarrojo por transformada de Fourier (FTIR) revelaron que existen bandas correspondientes de 740 cm-1 y 625 cm-1 debido a los enlaces Sn-O-Sn y Cu-O y estos incrementan con la concentración de dopante. En el estudio de la resistividad eléctrica se obtuvieron valores de 1.237x10-1 Ω-cm y 3.803x10-1 Ω-cm para una concentración de dopante de Cu de 5% y 10% presentando una reducción del 30% y un incremento del 112%, respectivamente, si son comparados con el valor de resistividad eléctrica del SnO2 de 1.792x10-1 Ω-cm. Respecto al efecto de la concentración de Cu en las películas de SnO2 sobre la sensibilidad en la detección de vapor de etanol. Se concluye que conforme aumenta la concentración de dopante de Cu, aumenta la sensibilidad y el tiempo de respuesta, siendo la película de SnO2:Cu (10%) la que presento mejor valor de sensibilidad y tiempo de detección al gas 85% y 36 s, respectivamente.
In this present work, was studied the effect of Cu concentration in tin dioxide thin films (SnO2) on their Sensitivity in the detection of ethanol vapor. These films were deposited on batches of silicon-platinum wafers (Si/Pt) at a synthesis temperature of 400°C using the pyrolytic spraying technique. In this work, the X-ray diffraction technique by crystals was used, verifying the presence of a characteristic cassiterite-type structure typical of SnO2; as well as the presence of Cu impurities due to the dopant in the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images revealed a change in the shape of the grains, becoming triangular due to the presence of Cu, and also showed an increase in surface roughness. Fourier transform infrared (FTIR) spectra revealed that there are corresponding bands at 740 cm-1 and 625 cm-1 due to Sn-O-Sn and Cu-O bonds and these increase with dopant concentration. In the study of electrical resistivity, values of 1.237x10-1 Ω-cm and 3.803x10-1 Ω-cm were obtained for a Cu dopant concentration of 5% and 10%, presenting a reduction of 30% and an increase of 112 %, respectively, if they are compared with the electrical resistivity value of SnO2 of 1.792x10-1 Ω-cm. Regarding the effect of Cu concentration in SnO2 films on the sensitivity in the detection of ethanol vapor. It is concluded that as the Cu dopant concentration increases, the sensitivity and response time increase, with the SnO2:Cu (10%) film being the one that presented the best sensitivity value and gas detection time of 85% and 36 s., respectively.
In this present work, was studied the effect of Cu concentration in tin dioxide thin films (SnO2) on their Sensitivity in the detection of ethanol vapor. These films were deposited on batches of silicon-platinum wafers (Si/Pt) at a synthesis temperature of 400°C using the pyrolytic spraying technique. In this work, the X-ray diffraction technique by crystals was used, verifying the presence of a characteristic cassiterite-type structure typical of SnO2; as well as the presence of Cu impurities due to the dopant in the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images revealed a change in the shape of the grains, becoming triangular due to the presence of Cu, and also showed an increase in surface roughness. Fourier transform infrared (FTIR) spectra revealed that there are corresponding bands at 740 cm-1 and 625 cm-1 due to Sn-O-Sn and Cu-O bonds and these increase with dopant concentration. In the study of electrical resistivity, values of 1.237x10-1 Ω-cm and 3.803x10-1 Ω-cm were obtained for a Cu dopant concentration of 5% and 10%, presenting a reduction of 30% and an increase of 112 %, respectively, if they are compared with the electrical resistivity value of SnO2 of 1.792x10-1 Ω-cm. Regarding the effect of Cu concentration in SnO2 films on the sensitivity in the detection of ethanol vapor. It is concluded that as the Cu dopant concentration increases, the sensitivity and response time increase, with the SnO2:Cu (10%) film being the one that presented the best sensitivity value and gas detection time of 85% and 36 s., respectively.
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Keywords
Película delgada, SnO2:Cu, Dopaje, Sensor de vapor, Spray pirolysis