Nanostructured Cu2ZnSnS4 (CZTS) thin film for self-powered broadband photodetection

Nanostructured materials exhibit broad spectral photodetection, strong light matter interaction and exotic optoelectronic properties compared to their bulk counterpart. To overcome the limitations of silicon based photodetectors, various nanomaterials have been investigated. Here we have used industrially viable stacked layer reactive sputtering method to grow rice-like nanostructured (rln) Cu2ZnSnS4 (CZTS) thin films. The rln-CZTS film showed optical absorption coefficient one order of magnitude greater than the plain thin films of CZTS. Further, even under zero bias condition, broad spectral response (in visible and near infrared range) was observed. The rise and decay time constants for visible (532 nm) and near infrared (NIR) (1064 nm) light incident were 208 ms, 175 ms and 681 ms, 778 ms, respectively (for 1 mV bias). The improvement in photocurrent has been attributed to enhanced light harvesting due to the presence of nanostructures in thin film. Detectivity of 4.48 x 10(8) Jones over a large area was observed indicating that rln-CZTS would be a potential material for other technical applications. Deposition of nanostructured CZTS using industrially viable reactive sputtering with short anneal and fabrication of self-powered broadband photodetection device with low rise and decay time constants are the novelties of this work. (C) 2017 Elsevier B.V. All rights reserved.