A New Strategy To Modulate Doping Of 2D Transistors

Researchers introduced a new strategy to fabricate two-dimensional semiconductor materials without any scattering effects.

Doping is a critical step in fabricating electronic devices with conventional semiconductor materials. The process of doping entails the introduction of impurities into semiconductors to alter the material’s optical, electrical, and structural properties.

However, many conventional doping strategies introduce too many carriers, leaving ionized dopants behind in the channel and obstructing the transport of charge carriers. Therefore, engineers have been trying to develop modulation doping techniques that separate ionized dopants from the channel.

With the emerging 2D material, it is important to modulate the doping strategies. To study these materials, and particularly to investigate quantum phenomena occurring within them, researchers should thus first eliminate unwanted scattering effects by modulating doping.

Researchers at Korea University and other institutes in Korea have introduced a strategy that could help to reduce intrinsic scattering effects in 2D semiconducting materials. The study enables the modulation of doping in 2D semiconductors through van der Waals (vdW) band engineering and remote charge transfer doping.

“We report the remote modulation doping of a two-dimensional transistor that consists of a band-modulated tungsten diselenide/hexagonal boron nitride/molybdenum disulfide heterostructure,” the researchers wrote in their paper. “The underlying molybdenum disulfide channel is remotely doped via controlled charge transfer from dopants on the tungsten diselenide surface.”

Using this approach, the researchers were able to realize a transistor that exhibited a reduced amount of intrinsic scattering. The approach significantly improved the carrier mobility. 

“The modulation-doped device exhibits two-dimensional-confined charge transport and the suppression of impurity scattering, shown by increasing mobility with decreasing temperature,” the researchers explained in their paper. “Our molybdenum disulfide modulation-doped field-effect transistors exhibit a room-temperature mobility of 60 cm2 V–1 s–1; in comparison, transistors that have been directly doped exhibit a mobility of 35 cm2 V–1 s–1.”

Researchers believe that their work could pave the way towards the development of faster and more efficient electronics based on semiconductors.

The research appeared in the journal Nature Electronics. 

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