High Resolution Image Download MS PowerPoint Slide The layered semiconductor Bi 2 O 2 Se is a promising candidate for next-generation nanoelectronic devices because it combines favorable electronic and structural properties. These include an exceptionally high electron mobility, a suitable bandgap and air stability, and most importantly, the ability to form a high-κ native oxide, Bi 2 SeO 5 (with a calculated bulk κ > 30). However, intrinsic point defects in the semiconductor and the oxide can influence the electronic behavior and long-term reliability. In this work, we employ density functional theory to investigate the electronic structure, formation energies, trap levels, and relaxation energies of the relevant native defects in both Bi 2 O 2 Se and β-Bi 2 SeO 5 . Our results demonstrate that selenium and oxygen vacancies in the semiconductor Bi 2 O 2 Se act as shallow donors, donating free electrons to the conduction band, consistent with the commonly observed unintentional n-type conductivity. In contrast, oxygen vacancies in the dielectric β-Bi 2 SeO 5 introduce deep-level trap states, indicating that they may act as performance-limiting charge trapping centers during device operation. We successfully correlate these theoretically identified defects with experimental device measurements from a prototype Bi 2 O 2 Se/β-Bi 2 SeO 5 field-effect transistor, structurally characterized via scanning transmission electron microscopy. We finally demonstrate the contribution of defects to critical reliability issues, specifically hysteresis and bias temperature instability. These insights provide input for reliability modeling and defect engineering strategies for improving the long-term stability of Bi 2 O 2 Se/Bi 2 SeO 5 -based nanoelectronics.
Bahrami et al. (Tue,) studied this question.