# Fabrication and Testing of Thermoelectric CMOS-MEMS Microgenerators with CNCs Film
## 4 Results  
The thermoelectric microgenerator contained two thermometers, where one was located at the hot part of the thermopiles and the other was located at the cold part of the thermopiles. The thermometer was employed to detect the temperature of HP and CP in the thermopiles. A heat chamber, a temperature detector, and a digital multimeter were used to measure the performance of the thermometers. The thermometers were set in a heat chamber. The heat chamber gave a heat source to the thermometers. The temperature detector calibrated the temperature in the heat chamber. The digital multimeter recorded the resistance change of the thermometers. Figure 12 shows resistance versus temperature in the thermometer. The results showed that the ratio of resistance and temperature at the cold part thermometer was the same as that at the hot part thermometer.  
The TMG performance was tested utilizing a heater, a cooler, a PID (proportional integral derivative) controller, and digital multimeters. The heater supplied heat to the microgenerator. The cooler provided cooling to the microgenerator. The PID controller was utilized to control the heat source of the heater and to control the function of the cooler. The digital multimeters measured the microgenerator OV and thermometers resistance. The thermometers in the microgenerator directly measured the TD of the cold and hot parts in the microgenerator.  
To characterize the heat absorption effect of the CNCs film, the microgenerator with the CNCs film and one without the CNCs film were tested, respectively. The microgenerator without  
Figure 11: SEM picture of the microgenerator with CNCs film.  
Figure 12: Measured resistance of the thermometers.  
the CNCs film was set on the testing system. The heat was given by heater, and cooling was supplied by the cooler. The thermometers measured the temperature difference of HP and CP in the microgenerator. Figure 13 reveals the measurement results of the microgenerator without the CNCs film. Then, the microgenerator with the CNCs film was tested. Figure 13 presents the measurement results of the microgenerator with the CNCs film. The results depicted that the temperature difference of the microgenerator with CNCs exceeded that without CNCs at the same heat source. The CNCs film had a heat absorption effect.  
The OV of the thermoelectric microgenerator with the CNCs film was tested. Figure 14 shows the measured OV of the microgenerator with the CNCs film. The measured results showed that the microgenerator OV was 3.3 mV at TD of 3 K. When comparing the experiment and simulation results, the error percentage of the microgenerator OV was 6%.  
The OP of the thermoelectric microgenerator with the CNCs film can be obtained in accordance with Equation (2). The initial resistance of the microgenerator was 21.8 k\(\Omega\). The measured OV as shown in Figure 14 and the initial resistance value were substituted into Equation (2), and the OP of the microgenerator with the CNCs film was obtained. Figure 15 depicts the measured OP of the  
Figure 14: Measured OV of the microgenerator.  
Figure 13: Temperature difference of the microgenerator.  
microgenerator. The results showed that the microgenerator OP was 125 pW at TD 3 K. Area of the microgenerator was 1.28 \(\times\) 1.2 \(\upmu\)m\({}^{2}\). According to the measured OV and OP of the microgenerator with the CNCs film, we evaluated the voltage factor and power factor of the microgenerator. The voltage factor of the microgenerator was 0.71 mV/K/mm\({}^{2}\), and its power factor was 9.04 pW/K\({}^{2}\)/mm\({}^{2}\). Table 1 shows a list of voltage and power factors for various thermoelectric microgenerators. As depicted in Table 1, the voltage factor and power factor of the microgenerator in this work exceed that of [PERSON] [27], [PERSON] [30], [PERSON] [31], [PERSON] [32], and [PERSON] [33].