Illumination-dependent free carrier screening effect on the performance evolution of ZnO piezotronic strain sensor

• Published in: Nano research 2016-04, Vol.9 (4), p.1091-1100
• Main Authors: Lin, Pei, Gu, Yousong, Yan, Xiaoqin, Lu, Shengnan, Zhang, Zheng, Zhang, Yue
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Carrier density; Chemistry and Materials Science; Compressive properties; Condensed Matter Physics; Devices; Evolution; Genetic screening; Illumination; Irradiation; Materials Science; Modulation; Nanotechnology; Optoelectronic devices; Performance degradation; Photoexcitation; Piezoelectricity; Polarization; Research Article; Response time; Screening; Sensors; Strain; Ultraviolet radiation; Zinc oxide; ZnO; 器件性能; 应变传感器; 极化电荷; 演变; 筛选; 紫外光照射; 自由载流子
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-016-1002-4

Performance modulation of ZnO optoelectronic devices in the presence of proper piezoelectric polarization charges has been widely reported, whereas relatively less work has been performed about the influence of photoexcitation on piezotronics. In this stud~ we experimentally investigated the performance evolution of ZnO piezotronic strain sensor under various 365 nm UV irradiation densities. The device demonstrated a response ratio of -200 under no illumination and under -0.53% compressive strain, and the response time is approximately 0.3 s. However, tremendous performance degradation was observed with the increase in the illumination densi~, which is attributed to the W-modulated change in the free electron concentration and Schottky barrier height. It was observed that increased carrier density intensifies the screening effect and thus, the modulation ability of piezo-polarization charges weakens. Meanwhile, the deterioration of rectifying behavior at the interface under UV illumination also jeopardizes the device performance.