Speaker
Description
Point defects play a critical role in semiconductors, offering opportunities to tailor and enhance device performance. Two-dimensional (2D) silicon carbide (SiC) is a recently synthesized layered material, but unlike bulk SiC, little is known about the effects of point defects in its monolayer form. In this study, hybrid density functional theory (DFT) was employed to investigate the formation, structural, electronic, and magnetic properties of N, P, As, Sb, and Bi dopants in 2D monolayer SiC. Under C-rich conditions, N, P, As, and Bi are energetically more favorable when substituted at C sites, whereas Sb is more stable at the Si site. The total magnetic moments induced by N, As, Sb, and Bi are stronger when doped at C sites than at Si sites. N consistently acts as an electron acceptor, while Bi behaves as an electron donor at both C and Si sites. P, As, and Sb can act as donors or acceptors depending on the substitution site. The defect concentration of N remains extremely low across all temperatures, whereas P shows significant thermal activation, maintaining a relatively high concentration even at 300 K. As defects are limitedly thermally activated but become favorable at elevated temperatures. Density of states analysis reveals that N, As, and Sb at C sites induce n-type semiconducting behavior, while Bi at a C site results in p-type behavior. Moreover, Sb, As, N, and P introduce sharp mid-gap states, and all dopants induce strong spin polarization. These findings provide theoretical insights into defect engineering in 2D monolayer SiC, highlighting its potential for future optoelectronic and electronic applications
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