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

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 (002) 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 x 10(3) at a bias voltage of 3 V and further increased to 130 x 10(3)% as the bias voltage was increased to 7 V. The quantum efficiency of the device was 0.66 x 10(3) and 1.8 x 10(3) at bias voltages of 3 and 7 V. respectively. (C) 2012 Elsevier Ltd. All rights reserved.