Preparation And Investigation On Thermoelectric Generators Based On Single Phosphorus Doped ZnO Microwires

ZnO is an II-VI clan direct wide band gap semiconductor materials and its band gap width is 3.37 eV. Due to its large exciton binding energy(60meV), it has been regarded as one of the most promising candidates for the next generation of ultraviolet(UV) light-emitting diode(LED). Recently, it has attracted great attention due to its potential in nanosystems as a nanogenerator.Currently, most researches of nanogenerators are piezoelectric drives, but there are few studies about using thermalenergy for generators. The mechanism of a thermoelectric generator which based on Seebeck is to drive the charge carriers to flow in the circuit by keeping a thermal gradient in the device. In this paper,the different phosphorus doping concentration ZnO microwires were grown by chemical vapor deposition method. On this basis, the thermoelectric generators based on single phosphorus doped ZnO microwires was fabricated, and discussed their output characteristics. Main content and innovation are as follows:(1) The different phosphorus doping large-scale ZnO microwires were grown by chemical vapor deposition method without using catalyst. The experimental results showed that the low phosphorus doping concentration ZnO microwires were intensive distribution, the average length was about 1.5cm, the direction was highly aligned and homogeneous, but the size of the ZnO microwires were not uniform and the length reduced with the increasing phosphorus concentration. By the EDS spectra, the phosphorus were detected, and we found that phosphorus concentration increased with the increasing P2O5 mass. In addition, it found that the ratio of the UV and green photoluminescence reduced with increasing phosphorus concentration.(2) A single p doped ZnO microwire thermoelectric generator based on thermoelectric energy conversion was fabricated. Through the control variable method on the preparation of nanometer generator out various of output signal was tested,and influence of the phosphorus doping concentration, the length, the temperature and the connection way for device were researched. It was found that the output signal increased with the increasing phosphorus doping concentration, the length, the temperature difference. Under a temperature difference of 77 K between the two electrodes of a single p-doped ZnO microwire, thermoelectric generator can give an output voltage of 44.2 mV and an output current of 100 nA. In addition, we calculated the Seebeck coefficient of a single phosphorus doped ZnO microwire was about 570μV/K. The experimental results can be for ZnO micro/nanostructure provides a research foundation in the application of thermoelectric generator.