Native point defects of semiconducting layered Bi2O2Se

Abstract

Bi2O2Se is an emerging semiconducting, air-stable layered material (Nat. Nanotechnol. 2017, 12, 530; Nano Lett. 2017, 17, 3021), potentially exceeding MoS2 and phosphorene in electron mobility and rivalling typical Van der Waals stacked layered materials in the next-generation high-speed and low-power electronics. Holding the promise of functional versatility, it is arousing rapidly growing interest from various disciplines, including optoelectronics, thermoelectronics and piezoelectronics. In this work, we comprehensively study the electrical properties of the native point defects in Bi2O2Se, as an essential step toward understanding the fundamentals of this material. The defect landscapes dependent on both Fermi energy and the chemical potentials of atomic constituents are investigated. Along with the bulk defect analysis, a complementary inspection of the surface properties, within the simple context of charge neutrality level model, elucidates the observed n-type characteristics of Bi2O2Se based FETs. This work provides important guide to engineer the defects of Bi2O2Se for desired properties, which is key to the successful application of this emerging layered material27.

T-square resistivity without Umklapp scattering in dilute metallic Bi2O2Se

“…Available Bi 2 O 2 Se single-crystals are metallic with extremely mobile carriers [21][22][23] . The insulator is doped by unavoidable defects, such as Se or O vacancies and Se-Bi antisite defects 24,25 .…”

“…Available Bi 2 O 2 Se single-crystals are metallic with extremely mobile carriers 21 – 23 . The insulator is doped by unavoidable defects, such as Se or O vacancies and Se–Bi antisite defects 24 , 25 . According to density functional theory (DFT) calculations 24 , the conduction band is centered at the Γ point of the Brillouin zone, following a parabolic dispersion (Fig.…”

Bi2O2Se:Bi2O5Se High‐K Stack as a 2D Analog of Si:SiO2: A First‐Principles Study

“…Defects in different charge states may induce defect levels at different energies [ 58 ] and may account for many device phenomena, such as Fermi level pinning [ 59 ] and conduction polarity. [ 41 ] These are worth studying in a future work.…”

“…The low interfacial trap density is correlated to the unique interfacial Se 2− layer (or a partly O 2− ‐substituted Se 2− layer) that electrostatically binds to BiO 1+ layers on either side of the interface, resulting in a highly Se vacancy defect tolerant interface because the interfacial Se vacancy defects, if any, are shallow. [ 41–43 ] Meanwhile, we do find that interfacial O vacancy defects can be problematic. The band offsets are found to be affected by the degree and the distribution of the isovalent O 2− substitution in the interfacial Se 2− layer.…”

Truly Concomitant and Independently Expressed Short‐ and Long‐Term Plasticity in a Bi2O2Se‐Based Three‐Terminal Memristor

“…Significant short‐term effect at a timescale longer than the normal dielectric relaxation time may indicate the involvement of certain slow ion processes that mediate the channel modulation. In this regard, the movement of interfacial Se anions are most likely because they are stabilized by weak electrostatic interaction and Se vacancies are shallow n‐type donors . The results of the alternating positive/negative V g pulse train measurements are shown in Figure S4 (Supporting Information), showing symmetric and stable multilevel resistive switching behavior.…”