Abstract
Metal-insulator-semiconductor-insulator-metal (MISIM) heterostructures, with rectifying current-voltage characteristics and photosensitivity in the visible and near-infrared spectra, are fabricated and studied. It is shown that the photocurrent can be enhanced by adding a multi-walled carbon nanotube film in the contact region to achieve a responsivity higher than under incandescent light of . The optoelectrical characteristics of the MISIM heterostructures are investigated at lower and higher biases and are explained by a band model based on two asymmetric back-to-back Schottky barriers. The forward current of the heterojunctions is due to majority-carrier injection over the lower barrier, while the reverse current exhibits two different conduction regimes corresponding to the diffusion of thermal/photo generated carriers and majority-carrier tunneling through the higher Schottky barrier. The two conduction regimes in reverse bias generate two plateaus, over which the photocurrent increases linearly with the light intensity that endows the detector with bias-controlled photocurrent.
Highlights
Carbon nanotubes (CNTs) have been attracting a lot of attention in the past three decades due to their remarkable chemical, mechanical, and electrical properties [1,2,3,4]
Photodetectors based on MWCNT [32,33,34] or SWCNT [35,36] films over Si have been the preferred devices for their fast response and high detection capability combined with easy fabrication, low cost, high reliability, and compatibility with existing technologies
We have shown that such heterostructures exhibit rectifying behavior, which we have explained by a band model based on two asymmetric Schottky barriers
Summary
Carbon nanotubes (CNTs) have been attracting a lot of attention in the past three decades due to their remarkable chemical, mechanical, and electrical properties [1,2,3,4]. The CNT type, whether single- or multi-walled, their quality and configuration in bundles or films of different density and thickness as well as the role of the semiconductor substrate in such hybrid structures have been widely investigated [14,29,30,31]. In this context, photodetectors based on MWCNT [32,33,34] or SWCNT [35,36] films over Si have been the preferred devices for their fast response and high detection capability combined with easy fabrication, low cost, high reliability, and compatibility with existing technologies. The presence of a MWCNT film in the contact region enhances the photoresponse of the device, mainly by increasing the photosensitive area of the junction
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
