Giant UV-sensitivity of ion beam irradiated nanocrystalline CdS thin films. Issue 5 (6th January 2016)

• Record Type: Journal Article
• Authors: Kumar, Pragati; Saxena, Nupur; Dewan, Sheetal; Singh, Fouran; Gupta, Vinay
• Is Part Of: RSC advances. Volume 6:Issue 5(2016)
• Page Start: 3642
• Page End: 3649
• Publication Date: 2016-01-06
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra21026g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A highly sensitive UV-detector is devised for the first time from ion beam irradiated nanocrystalline CdS thin films. The sensor exhibits improvements in the responsivity, photosensitivity, and efficiency as a function of ion fluence. Abstract : A highly sensitive UV-detector is devised for the first time from ion beam irradiated nanocrystalline CdS (nc-CdS) thin films. The UV-sensors are fabricated using pulsed laser deposited nc-CdS thin films on Si wafer and subsequent irradiation treatment. Swift heavy ion irradiation (SHII) of the nc-CdS thin films is carried out using 70 MeV 58 Ni 6+ ions. The sensors used in the present study are easy to fabricate and require inexpensive materials; they feature characteristics similar to those of UV sensors designed with complex structures and expensive procedures. Current–voltage ( I – V ) measurements reveal an enrichment in carrier concentration and improvement in conductivity after exposure to SHII. This giant conductivity may be attributed to an enhancement in sulfur vacancies as a consequence of SHII. The sensor exhibits improvements in the responsivity, photosensitivity, and efficiency as a function of the ion fluence and attains maximum values of ∼53 W A −1, 576.4% and 15.6 × 10 3 % respectively for a film irradiated at a fluence of 1 × 10 13 ions per cm 2 . The response time of the sensor reduces with the increase in ion fluence and reaches a minimum of a rise time of 165 ms and fall time of 65 ms at 3 V for these sensors. A possible mechanism involved in the SHII induced moderation of conductivity and consequently photosensitivity is explained on the basis of variation in the defect densities.