Advancing 2D Electronics: Modulation Doping and UWBG Semiconductors

In the pursuit of next-generation electronics, two-dimensional (2D) semiconductors are on the brink of transforming the industry with their compactness and low power consumption. Yet, widespread adoption is hindered by challenges such as high contact resistance and inefficient doping techniques. Addressing these issues, our research first investigates workfunction-mediated charge transfer, known as modulation doping, to enhance the performance of p-type 2D transistors. By focusing on type-III band alignment, we examine 27 potential dopant materials, including transition metal oxides, oxyhalides, and RuCl₃, for use with channel materials like transition metal dichalcogenides (TMDs) and group-III nitrides. Extensive first-principles density functional theory (DFT) simulations reveal the significant p-type doping capabilities of materials such as RuCl₃, MoO₃, and V₂O₅, which effectively reduce contact resistance and enhance channel mobility through efficient hole transfer without adverse defects. Simultaneously, ultra-wide bandgap (UWBG) semiconductors are set to redefine power electronics by surpassing traditional wide bandgap materials like GaN and SiC, with their ability to function at higher voltages, frequencies, and temperatures. Our exploration extends into the UWBG realm with monolayers of boron-based group-III nitride alloys, identified as B_xM_1-xN (where M = Al, Ga). Through ab initio calculations, we discover several energetically and dynamically stable structures, attributing their stability to an unexpected out-of-plane displacement, which induces polar ordering and an antiferroelectric ground state. Together, these efforts illuminate the potential of combining modulation doping and UWBG semiconductor strategies to overcome current limitations in 2D electronic devices. By identifying stable, efficient materials and structures, our comprehensive study paves the way for innovative, high-performance electronics that leverage the unique properties of 2D semiconductors, advancing the field towards practical, industry-wide applications.