title: Manipulation of Optoelectronic Properties and Band Structure Engineering of Ultrathin Te Nanowires by Chemical Adsorption.
abstract: Band structure engineering is a powerful technique both for the design of new semiconductor materials and for imparting new functionalities to existing ones. In this article, we present a novel and versatile technique to achieve this by surface adsorption on low dimensional systems. As a specific example, we demonstrate, through detailed experiments and ab initio simulations, the controlled modification of band structure in ultrathin Te nanowires due to NO2adsorption. Measurements of the temperature dependence of resistivity of single ultrathin Te nanowire field-effect transistor (FET) devices exposed to increasing amounts of NO2reveal a gradual transition from a semiconducting to a metallic state. Gradual quenching of vibrational Raman modes of Te with increasing concentration of NO2supports the appearance of a metallic state in NO2adsorbed Te. Ab initio simulations attribute these observations to the appearance of midgap states in NO2adsorbed Te nanowires. Our results provide fundamental insights into the effects of ambient on the electronic structures of low-dimensional materials and can be exploited for designing novel chemical sensors.
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Ahin
authors.initials: A
authors.lastname: Roy
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Kazi Rafsanjani
authors.initials: KR
authors.lastname: Amin
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Shalini
authors.initials: S
authors.lastname: Tripathi
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Sangram
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Abhishek K
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Aveek
authors.identifier: http://orcid.org/0000-0002-2378-7980
authors.initials: A
authors.lastname: Bid
authors.affiliation: Materials Research Centre and §Department of Physics, Indian Institute of Science , Bangalore 560012, India.
authors.forename: N
authors.identifier: http://orcid.org/0000-0003-0012-046X
authors.initials: N
authors.lastname: Ravishankar
keywords: S-M transition; adsorption; band-structure engineering; electronic transport; nanowire; tellurium