2D Tin Monoxide—An Unexplored p‐Type van der Waals Semiconductor: Material Characteristics and Field Effect Transistors

Abstract

2D materials are considered promising candidates for developing next‐generation high‐performance energy efficient electronic, optoelectronic, and valley‐tronic devices. Though metal oxides are widely used in the fabrication of many advanced devices, very little work has been reported on their properties in 2D limit. This article reports the discovery of a new 2D materials system, 2D tin monoxide (SnO). Layer by layer growth of SnO on sapphire and SiO2 substrates is demonstrated using a pulsed laser deposition method. The number of SnO layers is controlled by controlling the number of laser shots during the deposition process. Raman spectroscopic and X‐ray photoelectron spectroscopic analysis confirms the formation of phase pure SnO layers. Field effect transistors (FETs) using few layer SnO channels grown on SiO2 substrates are successfully fabricated. These FETs show typical p‐channel conduction with field effect mobility ranging from 0.05 to 1.9 cm2 V−1 s−1. Field effect mobility varies with the number of SnO layers and decreases on either sides of the optimum layer numbers (12), which is explained based on charge screening and interlayer coupling in layered materials.

Layer‐Dependent Optoelectronic Properties of 2D van der Waals SnS Grown by Pulsed Laser Deposition

“…The mobility starts to decrease when further increasing the number of layers to 25 ML. A thickness dependent mobility µ FE has been reported for other FETs based on 2D materials, including SnO, [56] MoS 2 [57,58] and BP, [59,60] which can be accounted for by screening effects and interlayer coupling in the layered materials. In back-gated FETs based on 2D materials µ FE is mainly limited by scattering resulting from charged impurities in the SiO 2 .…”

Ultrathin MoO2 nanosheets with good thermal stability and high conductivity

“…These conductivities are just above the results of MoO 2 nanorods, and much higher than the conductivities of other 2D compounds such as transition metal dichalcogenides, black phosphorus, and SnO. 2,[34][35][36][37] The exceptionally high conductivity of individual MoO 2 nanosheet is ascribed to the unique crystal structure. To the best of our knowledge, the m-MoO 2 crystal has a rutile-type structure, which is built up by MoO 6 octahedral units (see inset of Fig.…”

Lone-Pair Stabilization in Transparent Amorphous Tin Oxides: A Potential Route to p-Type Conduction Pathways

“…SnO and other lone-pair active, post- transition metal oxides can have a raised and delocalized valence band edge due to a complex hybridization between the O 2p, and metal s-and p-orbitals. [14][15][16][17][18][19][20] Moreover, in SnO this hybridization results in a small (~0.7eV), indirect, electronic band gap which enables bipolar doping without curtailing optical transparency. [21][22][23] However, these orbital interactions have only been thoroughly examined within the context of layered crystal structures incorporating a lone-pair distortion.…”