Degradation of 2D materials
Semiconductors
Semiconducting materials are widely used in electronic devices due to their unique electronic properties, such as their ability to control the flow of electricity and their potential for use in solar cells and transistors. However, these materials are also prone to degradation under ambient conditions, which can greatly affect their performance and lifetime.
Environmental factors
One of the main concerns with semiconducting materials is the degradation of their crystal structure. This can occur due to exposure to environmental factors such as humidity, temperature, and UV radiation. In particular, 2D materials, which are composed of a single layer of atoms, are extremely sensitive to these factors and can degrade rapidly under ambient conditions.
One of the main factors that accelerate the degradation of 2D materials is the presence of moisture. When exposed to humidity, the crystal structure of 2D materials can become distorted, leading to defects and impurities in the material. This can greatly affect the electronic properties of the material, such as its bandgap and conductivity, and can result in decreased performance of electronic devices.
Oxidation
The oxidation of 2D materials refers to the process by which these materials react with oxygen to form an oxide layer or isolated molecule on their surface. This phenomenon can occur through various mechanisms, such as chemical reactions between the surface atoms of the 2D material and oxygen molecules in the air, or through exposure to high temperatures this process can be accelerated. The extent of oxidation can vary depending on factors such as the composition of the 2D material and the conditions under which it is exposed to oxygen. The resulting oxide layer can have a significant impact on the properties and performance of the 2D material, such as affecting its electrical conductivity, mechanical strength, and chemical stability. Therefore, understanding and controlling the oxidation of 2D materials is an important area of research in the field of materials science.
Exposure to radiation
Another factor that can lead to the degradation of 2D materials is exposure to UV radiation. This can cause the formation of defects in the crystal structure and can also lead to the generation of free carriers, which can affect the electrical properties of the material.
Two examples of 2D materials that are known to degrade under ambient conditions are PtSe2 and MoTe2. PtSe2 is a semimetallic material that has been shown to degrade rapidly under ambient conditions due to the presence of moisture. MoTe2, on the other hand, has been shown to degrade under UV radiation and air molecules.
Effect of liquids
Another concern with 2D materials is the degradation of the crystals inside liquids. For example, when 2D materials are exposed to water, they can degrade rapidly due to the formation of defects and impurities in the crystal structure. This can greatly affect the electronic properties of the material and can result in decreased performance of electronic devices. For example, when the crystal structure of a 2D material is degraded, it can lead to decreased conductivity and increased resistance.
Detecting the effect
To detect degradation in 2D materials, characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) can be used, although these are one of many characterization techniques These techniques can provide detailed information on the crystal structure and electronic properties of the material, allowing for the identification of defects and impurities.
Preventing the degradation
To prevent 2D materials from degrading under ambient conditions, several strategies can be employed. One strategy is to encapsulate the material in a protective layer, such as a polymer or metal, to prevent exposure to environmental factors. Another strategy is to use 2D materials that are less susceptible to degradation, such as molybdenum disulfide (MoS2) or graphene.
Conclusion
The degradation of semiconducting materials under ambient conditions is a major concern in the electronic industry, especially for 2D materials. The degradation can occur due to various factors such as humidity, temperature, and UV radiation. The degradation of 2D crystal structure will greatly affect the electronic properties of the materials and the performance of the devices. Characterization techniques such as SEM, TEM, and XRD can be used to detect degradation, and strategies such as encapsulation and using less susceptible 2D materials can be used to prevent degradation.
Author: Δ Emad Najafidehaghani Δ
