In Situ Detection of Local Structure Transformation of 2D SnSe Nanosheets through Nanothermomechanical Behavior

Abstract

2D tin selenide (SnSe) is a promising semiconductive material and its thermal stability is one of the most significant evaluating indicators. However, few works are involved in the temperature‐dependent structure stability of 2D SnSe nanosheets. Herein, local structure transformation of a 2D SnSe nanosheet into SnSe2 under high temperature is characterized by a novel atomic force microscope (AFM)‐based nanoscale thermomechanical method. Based on an AFM platform, the temperature‐dependent nanomechanical properties are investigated. A softness process is found to occur upon the surface of 2D SnSe, accompanying the structure transformation under high temperature. It means that the generation of SnSe2 is due to the structure collapse of SnSe, stemming from the evaporation of Sn atoms under about 90 °C. The transformation mechanism is further verified by a real‐time nanothermomechanical method. A deeper understanding of the thermal stability and thermal decomposition mechanism of 2D SnSe is promoted. The improved in situ nanomechanical method offers a highly sensitive method to probing the nanomechanical properties of 2D materials.

Wafer-Scale Production of Two-Dimensional Tin Monoselenide: Expandable Synthetic Platform for van der Waals Semiconductor-Based Broadband Photodetectors

“…Previously, the structural collapse of 2D SnSe was occurred at 90 °C by the evaporation of Sn atoms, as ascertained by the atomic force microscopy (AFM)-based thermomechanical analysis at elevated temperatures. 34 We infer that the localized oxidation of SnSe at the uppermost layer caused by Se vacancies might be a contributing factor to the excellent stability of the 2D SnSe multilayers observed under extremely oxidative conditions. The localized oxidation behavior can be determined by the crystallinity of the 2D material because oxidation is limited to the uppermost atomic layer of crystalline 2D materials, whereas oxygen can diffuse into amorphous and nanocrystalline structures.…”

“…This unexpected result may be attributed to the decrease in the contact resistance at the interface between the SnSe layer and Au metal induced by the heat-driven elimination of redundant water molecules. Previously, the structural collapse of 2D SnSe was occurred at 90 °C by the evaporation of Sn atoms, as ascertained by the atomic force microscopy (AFM)-based thermomechanical analysis at elevated temperatures . We infer that the localized oxidation of SnSe at the uppermost layer caused by Se vacancies might be a contributing factor to the excellent stability of the 2D SnSe multilayers observed under extremely oxidative conditions.…”

Direct Observation of Local Dielectric Conductive Paths and Their Dynamics in the Degraded Multilayer Ceramic Capacitors

“…Here, considering the difference of thermal conductivity between local dielectric layer (lower thermal conductive, insulate‐like phase) and local conductive path (higher thermal conductive, metal‐like phase), we proposed scanning thermal microscopy, a powerful tool for local thermal physics characterization, [ 29–36 ] to perform direct imaging of the degraded MLCCs by the highly accelerated life test (HALT) method, and successfully obtained local dielectric conductive paths and their electrical tree dynamic behaviors under the dc bias on and off state. Such new demonstrations provide us a direct, unique view to understand local breakdown phenomena and undoubtedly enrich our insights in the insulation degradation and reliability of MLCCs.…”

“…[15][16][17][18][19][20][21][22][23][24] However, for the dielectric breakdown conductive path and its dynamics under electric fields, it is still in the frame of theoretical modeling process, and few studies have been done in the direct imaging of the local conductive path, [25] and their dynamics in response to the loading fields, which gives a great limitation to understanding local degradation mechanism for MLCCs' failure. [26][27][28] Here, considering the difference of thermal conductivity between local dielectric layer (lower thermal conductive, insulatelike phase) and local conductive path (higher thermal conductive, metal-like phase), we proposed scanning thermal microscopy, a powerful tool for local thermal physics characterization, [29][30][31][32][33][34][35][36] to perform direct imaging of the degraded MLCCs by the highly accelerated life test (HALT) method, and successfully obtained local dielectric conductive paths and their electrical tree dynamic behaviors under the dc bias on and off state. Such new demonstrations provide us a direct, unique view to understand local breakdown phenomena and undoubtedly enrich our insights in the insulation degradation and reliability of MLCCs.…”

Revealing the Anisotropic Structural and Electrical Stabilities of 2D SnSe under Harsh Environments: Alkaline Environment and Mechanical Strain

“…Bulk SnSe is traditionally considered environmentally stable and only suffers a lower symmetry ( Pnma (#62)) to a higher symmetry ( Cnma (#63)) phase transition at 750–800 K . Since the structural transition can sharply reduce its thermoelectric properties, the structural stability of SnSe has recently attracted a lot of research interests.…”