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Photoconductive properties of Er-CdSe nanobelt detectors

Huang, Jieqing, Tan, Qiuhong, Zhang, Zijing, Wang, Qianjin, Feng, Xiaobo, Liu, Yingkai
Journal of materials science 2019 v.54 no.1 pp. 560-570
cadmium, detectors, erbium, nanoparticles, selenium, tungsten
Three kinds of devices based on single Er-doped CdSe nanobelt (Er-CdSe NB), single CdSe NB and four CdSe NBs in parallel were constructed by hard mask assisted with 10-μm tungsten wire in diameter. The photoelectronic properties of three kinds of devices were investigated. It is found that the dark currents of Er-CdSe NB and CdSe NB (four CdSe NBs in parallel) are 4 × 10⁻¹⁰ and 1.0 × 10⁻¹³ A (8.92 × 10⁻¹¹ A). They have high Iₒₙ/Iₒff ratios with 2.21 × 10⁴ and 8.97 × 10⁵ (4.61 × 10⁴), respectively. The corresponding responsivity, external quantum efficiency and detectivity of Er-CdSe NB and CdSe NB (four CdSe NBs in parallel) are 2.17 × 10³, 3.87 × 10⁵ and 2.27 × 10¹² A/W; 3.84, 692 and 2.9 × 10¹¹; 1.59 × 10², 2.86 × 10⁴ and 4.96 × 10¹¹ Jones. The responsivity Rλ and external quantum η of four CdSe NBs in parallel are higher by two orders of magnitude than that of single CdSe NB device. The detectivity D* of the former is twofold higher than that of the latter. In the meantime, Rλ, η and D* of Er-CdSe NB are 10-fold higher than those of four CdSe NBs in parallel. The superior performance of the Er-CdS NB device offers an avenue to develop highly sensitive photodetector applications.