The majority of two-dimensional (2D) transition metal disulfides (TMDCs) are semiconductors with intrinsic band gap structures and high light absorption. They show promise in a wide range of electrical, optoelectronic, and energy storage applications. Plasma treatment is particularly useful for a wide range of nanoscale 2D TMDC material alterations due to its unique controlled, effective method and energy efficiency.
Alfa Chemistry recently completed substantial research on plasma treatment technology, which may provide surface modification services to clients' TMDC materials. This is a viable and unique approach as a way to modulate the properties of TMDC materials. The main functions of our TMDC material plasma modification include etch thinning, n-type or p-type doping, phase change from 2H to 1T, vacancy defect repair, construction of heterostructures and self-limiting protective layer formation. For assistance with your material modification, please contact us.
Plasma Surface Modification of TMDC
Alfa Chemistry creates unique TMDC plasma surface modification services for our customers by combining specialist plasma treatment technology with our knowledge and expertise.
The following are our plasma modification capabilities for TMDC materials.
Plasma Modification of Optical Properties
One of the most common uses is plasma thinning of 2D TMDC, and Alfa Chemistry has a number of plasma processes for thinning multilayer TMDC materials, including etching layer by layer to a single layer. An atomic layer etching (ALE) approach, which comprises of two processes, namely a radical adsorption step and a reactive compound desorption step by low energy Ar+ ion exposure, is one of the most extensively utilized procedures. This approach is suitable for multilayer TMDC materials because it provides fine layer-by-layer thinning.
The structure of TMDCs always contains a large number of different types of defects that play an important role in optical and other properties. Alfa Chemistry uses low temperature plasma to provide a convenient and highly flexible method for defect engineering in TMDCs. We can modulate the PL strength of TMDC materials through plasma treatment. For example, by increasing the oxygen plasma exposure time, the PL of monolayer MoS2 sheets is gradually reduced from a very high intensity to complete bursting.
- Surface functionalization
We frequently use plasma-induced doping and surface passivation to alter the optical characteristics of 2D TMDC materials. Many investigations have focused on using plasma treatment to dope TMDCs with heteroatoms to create controlled and stable photoluminescence.
Fig 1. Diverse plasma effects in the modification of 2D transition metal dichalcogenides. (Nan H, et al. 2019)
Plasma Modification of Electronic/Optoelectronic Properties
High electrical contact resistance between the metal/channel interface is a major obstacle to exploring electrical transport properties in TMDC devices. Alfa Chemistry developed a selective area plasma etching process in the top h-BN protective layer to achieve ohmic contacts in many 2D TMDC materials at low temperatures. The exposed top h-BN layer is etched by O2 plasma at a relatively high rate with little effect on the bottom TMDC material.
In silicon-based semiconductor technology, doping is one of the most important methods to facilitate the realization of versatile electronic devices. Alfa Chemistry offers a gentle, low-damage plasma-based doping process for ultrathin characterized TMDCs, with the added advantage of high controllability and excellent selectivity.
Alfa Chemistry has been able to unlock substantial prospects by using plasma surface modification to change the use of TMDC in the composites industry. The plasma treatment technology ensures an environmentally friendly, high quality and consistent treatment. Furthermore, the technique expands graphene's potential applications in real industrial applications. Our plasma modification technology gives Alfa Chemistry confidence.
Reference
- Nan H, et al. (2018). "Recent Advances in Plasma Modification of 2D Transition Metal Dichalcogenides." Nanoscale. 11: 19202-19213.
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