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Growth and characterization of CdS single-crystalline micro-rod photodetector

2012; Elsevier BV; Volume: 54; Linguagem: Inglês

10.1016/j.spmi.2012.11.005

1096-3677

M.A. Mahdi, J.J. Hassan, Naser M. Ahmed, S.S. Ng, Z. Hassan,

Chalcogenide Semiconductor Thin Films

The fabrication of high-quality photodetection devices has received considerable attention. The crystalline structure of the material plays an influential role on the properties of the fabrication device. In this study, single-crystalline CdS micro-rods were grown via the thermal evaporation method and were fully characterized to determine their potential for application in high-photosensitivity photodetectors. The CdS rods were grown in various diameters, with a wurtzite (hexagonal) structure oriented strongly toward the (0 0 2) plane. Photoluminescence measurement of the grown CdS micro-rods showed two emission bands at 503 and 623 nm. The current–voltage characteristics of the Al/CdS single rod indicated that the device was highly sensitive to ambient light. The photoconductivity of the fabricated Al/CdS single rod device showed a peak at 480 nm. The photocurrent rise and decay times were investigated under 460 nm chopped light and at bias voltages of 3, 5, and 7 V. The device had a faster response at a bias voltage of 7 V than at other applied voltages. Furthermore, the photosensitivity of the device reached 0.82 × 103 at a bias voltage of 3 V and further increased to 130 × 103% as the bias voltage was increased to 7 V. The quantum efficiency of the device was 0.66 × 103 and 1.8 × 103 at bias voltages of 3 and 7 V, respectively.