Molecular doping of transition metal dichalcogenides using metal phythalocyanines

Abstract

Control of carrier type and density through doping of semiconducting transition metal dichalcogenides (TMDs) is critical for their applications in electronic and optoelectronic devices. In this work, we explore a group of phythalocyannie (Pc) molecules that can chelate with various metal elements from the periodic table, providing a wide range of doping levels. Unlike other substitutional doping distorting TMD lattices, these Pc molecules dope the TMD channels through surface charge transfer [1]. By using metal substituents with different work functions, such as Pt, Cu, Fe, and Na in phythalocyannies, we are able to tune the doping level and polarity of TMD devices. We achieved the highest doping levels for phsioabsorbed species up to date. Unlike other dopants exhibiting unstable doping effects [2], these Pc compounds offering high doping levels remain almost unchanged even weeks after initial doping. These Pc molecules can chelate up to 70 different elements from the periodic table [3] and potentially providing vastly different properties to TMD devices.