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Free and open to the public


Research Pavilion, Room 475 (NanoScience Technology Center)


Several transition metal dichalcogenides are semiconductors which, similarly to graphene, are composed of van der Waals coupled atomic layers. When exfoliated down to a single atomic layer, a transition from an indirect to a direct band gap is observed suggesting their suitability for electronics and optoelectronics. In fact, several classes of high-performance devices have already been reported along with significant progress in understanding their physical properties. Here, we will provide a very brief overview on the field and discuss experimental studies which further unravel their potential for optoelectronic applications. In particular, we will discuss initial results on multilayered WSe2 field-effect transistors which indicate extremely high photoresponsivities, i.e. in excess of ~7 A/W, along with photo response times ranging from τ ~5 μs to 40 μs, which are promising values for photo detecting applications. We will also discuss the observation of a hitherto unreported electro-optical effect, namely light-induced diode like response in MoSe2 field-effect transistors whose sense of current rectification can be controlled by a gate voltage. This effect could lead to a new type of optoelectronic switch. Finally, we will present results from electrostatically gated MoSe2 PN junctions, unveiling photovoltaic conversion efficiencies exceeding 10% under white light illumination from devices composed of approximately 10 atomic layers. All these observations underline the particularly strong interaction between light and charge carriers in these systems.


Luis Balicas, Ph.D.

Distinguished University Scholar

Condensed Matter Sciences

National High Magnetic Field Laboratory

Florida State University


Rebeca Barrios NanoScience Technology Center 407-882-1515