Development of MWCNTs-based wideband photodetector in the visible range: wavelength and power-dependent response studies

Photosensitive detector has been reproducibly fabricated using MWCNTs random network-based film grown by chemical vapor deposition technique. For the first time, excellent photoconductive response is reported over the entire green to red band (508-680 nm) of the visible light with maximum efficiency. Wavelength-dependent studies as well as white light exposure confirm the achievement of significant response in the entire visible region which is in commensurate with the absorption spectra of the detection element. The other remarkable novelties of this work are its fast response and recovery time, excellent repeatability and no drift over a time span of 1 year. Besides, there is no local heating effect observed due to photon flux density up to 1,800 lux/m(2). The sensing mechanism is explained by interband transition of free carriers, and there is no heat-induced e-h pair generation. The results have opened up the possibility of reproducible fabrication of such device applicable for optical detector or CCD for visible light detection.