Thermopile Infrared Detector with Detectivity Greater Than 108 cmHz(1/2)/W

Abstract

In this paper, the design, fabrication and experimental results of the thermopile infrared detector, with a single layer of low-stress SiN x membrane, instead of thin sandwich layer membrane of SiO 2 -Si 3 N 4 are presented. Thermal isolation is achieved by using back etching of bulk silicon. Thermopiles are consisted of serially interconnected p-poly-Si/Al thermocouples supported by the single layer of SiN x membrane with low stress. Au/Ti reflective coating was evaporated on the surface of cold junctions of the thermopile to block incident radiation. In the measurement, we find that infrared absorbance of SiN x membrane to different wavelength is diverse and less than 100%, which has great influence on calculating the actual absorbing power of the detector, so the infrared (IR) transmission spectrum is measured to calibrate the actual infrared absorbing amount of the detector. The analysis result shows that only 43.72% infrared radiation is absorbed by the detector. Based on the measurement of IR transmission spectrum and output voltage of the detector, the response sensitivity of the detector is calculated as 31.65 V/W, detectivity of the detector is 1.16×10 8 cmHz (1/2) W −1 , and response time of the detector is 126 ms.

Highdetectivity AlInSb Midinfrared Photodiode Sensors with Dislocation Filter Layers for Gas Sensing

“…The sample with the DFLs had a detectivity of 1.7 × 10 9 cm √Hz W −1 around 3.3 μm, which was more than twice that of the reference sample. This value is also higher than other sensors, such as thermopiles and pyroelectric sensors …”

Thermoelectric Photosensor Based on Ultrathin Single-Crystalline Si Films †

“…The linear increase of the Seebeck voltage, V S , was due to the temperature difference induced by the laser beam between the central region and the silicon frame (black circles). The responsivity, R S , of the TE sensor, defined as the ratio between the output voltage and the absorbed power [16,17,18], was determined by the slope in Figure 3. R S amounted to 13 V/W and yielded an outstanding value of 2.6 × 10 7 V/Wm 2 in air, considering the small area of the device.…”

“…By fitting the voltage curve in Figure 5a, it was also possible to determine the response time of the device, which was ~4.3 ms. The detectivity was evaluated using the equation D*=RS·A/4kTR [16,17,18], where R S is the responsivity, A the area of the sensing zone, k the Boltzmann constant, T the temperature and R the internal resistance of the device. D* = 2.86×107 cmHz(1/2)W−1 compared well with other thermoelectric-based CMOS-compatible sensors considering the reduced thermal constant of the device [16].…”

High photoresponse inverted ultraviolet photodectectors consisting of iridium phosphor doped into poly(N-vinylcarbazole) polymeric matrix

“…The sensitivity of (t-bt) 2 Ir(acac) doped device is 6.3 Â 10 10 cm Hz 1/2 /W at À3 V, comparable to some inorganic UV-PDs. 29 However, despite of the high gain in R, D* is relatively less than the reported UV-OPDs mainly due to the high dark current density. From the energy band diagram in Figure 1(c), we can see that the electron barrier of 1.4 eV between the work function of Ag and the lowest unoccupied molecular orbital level of (t-bt) 2 Ir(acac) is much lower than the hole barrier of 2.7 eV between the work function of ITO and the valence band of ZnO x .…”