Investigation of semiconducting YBaCuO thin films: A new room temperature bolometer

Abstract

Articles you may be interested inCrystallization and pyroelectric effect of semiconducting YBaCuO thin films deposited at different temperatures A sensitive YBaCuO thin film bolometer with ultrawide wavelength responseWe explore the application of the semiconducting phases of YBaCuO thin films as a bolometer for uncooled infrared detection. For this study, four different structures were built with different types of buffer layers: YBaCuO on a Si substrate with and without a MgO buffer layer, and on an oxidized Si substrate with and without a MgO buffer layer. These films were all amorphous without a detectable long range order. For comparison, crystalline tetragonal YBa 2 Cu 3 O 6.5 and YBa 2 Cu 3 O 6.3 thin films on a LaAlO 3 substrate were included into the study. All six films exhibited semiconducting resistance versus temperature characteristics. The bolometer figures of merit, responsivity, and detectivity were calculated from the measured temperature coefficient of resistance ͑TCR͒ and the inherent noise characteristics of the temperature sensing element. The room temperature TCRs for all four amorphous films were greater than 2.5% K Ϫ1 . The highest TCR of 4.02% K Ϫ1 was observed on the amorphous YBaCuO thin film deposited on MgO/Si without a SiO 2 layer. The TCR of the tetragonal films, on the other hand, remained 2% K Ϫ1 or less in the same temperature range. Noise measurements performed in the 1-100 Hz frequency range revealed a quadratic dependence on the bias current as would be expected from ohmic electrical characteristics. The Johnson and 1/f regions were clearly identified in the noise spectrum. From TCR and noise measurements, we estimated the amorphous semiconducting YBaCuO bolometers would have a responsivity as high as 3.8ϫ10 5 V/W and a detectivity as high as 1.6ϫ10 9 cm Hz 1/2 /W for 1 A bias current and frame frequency of 30 Hz if integrated with a typical air-gap thermal isolation structure.

High Temperature-Coefficient of Resistance at Room Temperature in W-Doped VO2 Thin Films on Al2O3 Substrate and Their Thickness Dependence

“…The TCR max , defined as the average of two TCR curves with the hysteresis, were À74:8%/K at T max ¼ 337 K, À24:1%/K at 315 K, À12:0%/K at 298 K, and À7:8%/K at 284 K for the films of x ¼ 0, 0.01, 0.015, and 0.02, respectively. These TCR values are larger than those in the other materi-als, 6,8,[15][16][17][18][19][20] as shown in Fig. 4(a).…”

Short Term Innovative Research on Sensors on Flexible Substrates

“…It is found to be approximately -3.1 % at room temperature. This is a very typical value for a semiconducting YBCO [2,11]. The measured R-T and calculated TCR graph can be seen in Fig.…”

“…The last deposition step was to sputter a 4000 Ä YBCO thin film at room temperature [11]. The YBCO thermometers were patterned by wet etching with a 1:100 aluminum etch solution at room temperature.…”

Measuring fluence distribution of excimer laser with YBCO film light thermodetector

“…Anisotropy crystal materials have Seebeck effect too, in generally it can be expressed E=SAT (1) where A T is the temperature gradient, is Seebeck tensor of a crystal, i is the thermoelectric field. For example, in the thermocouple, a voltage appears between the two sides when there is a temperature difference.…”