Posted in | News | LEDs | Optics and Photonics

Novel van der Waals Heterostructure for Mid-Infrared Light-Emission Applications

Mid-infrared (MIR) spectra fine extensive applications for communications, molecule characterizations, and thermal imaging. In MIR technologies, the MIR light source is the main component. MIR light-emitting diodes (LED) offer portability, narrow linewidth, and low power consumption.

(a) Schematic diagram of the BP-WSe2 heterostructure. Under the excitation of light, the electron and hole pairs in WSe2 can be efficiently transmitted to BP, thereby enhancing its MIR photoluminescence. (b) Schematic diagram of the BP-MoS2 heterojunction diode. Under a positive bias voltage between BP and MoS2, the electrons on the conduction band of MoS2 can overcome the barrier, enter into the conduction band of BP, and recombine with abundant holes in BP. Thereby electroluminescence is achieved. Image Credit: by Xinrong Zong, Huamin Hu, Gang Ouyang, Jingwei Wang, Run Shi, Le Zhang, Qingsheng Zeng, Chao Zhu, Shouheng Chen, Chun Cheng, Bing Wang, Han Zhang, Zheng Liu, Wei Huang, Taihong Wang, Lin Wang, and Xiaolong Chen.

After the rediscovery of thin-film Black Phosphorus (BP) in 2014, it has gained much attention because of its special properties, such as tunable bandgap, high carrier mobility, and in-plane anisotropy, etc. All these make BP a potential material for applications in optoelectronics and electronics.

BP contains a thickness-dependent (0.3 to 2 eV) bandgap, the size of which can be further manipulated by adding a chemical doping or external electric field. Thus, thin-film BP has been considered as a star MIR material.

Earlier studies primarily concentrated on few-layer BP flakes (with less than five layers) and luminescence properties of the monolayer. But new studies show that thin-film BP (with more than seven layers) exhibits notable photoluminescence properties in the MIR region.

Scientists have hypothesized a novel van der Waals (vdW) heterostructure for MIR light-emission applications, which has been developed from BP and TMDC (like MoS2 and WSe2).

The BP-WSe2 heterostructure develops a type-I band alignment as per the DFT calculation. Thus, the hole and electron pairs in the monolayer WSe2 can be transported efficiently into the narrow-bandgap BP, thus improving the MIR photoluminescence of thin-film BP. An enhancement factor of approximately 200% was obtained in the 5nm-thick BP-WSe2 heterostructure.

At the same time, the BP-MoS2 heterostructure develops a type-II band alignment. A natural PN junction is developed at the interface between p-type BP and n-type MoS2. Upon applying a positive voltage bias between MoS2 (Vds > 0) and BP, electrons in the conduction band of MoS2 can cross the barrier and make their way into the conduction band of BP.

Simultaneously, most holes are blocked at the interface within BP because of the huge Schottky barrier of the valence band. Consequently, an efficient MIR electroluminescence is realized in the BP-MoS2 heterostructure.

The BP-TMDC vdW heterostructures exhibit several advantages, like good compatibility with silicon technology, high efficiency, and simple fabrication process. Thus, it offers a potential platform for examining silicon-2D hybrid optoelectronic systems.

Journal Reference:

Zong X., et al. (2020) Black phosphorus-based van der Waals heterostructures for mid-infrared light-emission applications. Light: Science & Applications. doi.org/10.1038/s41377-020-00356-x.

Source: http://english.ciomp.cas.cn/

Tell Us What You Think

Do you have a review, update or anything you would like to add to this news story?

Leave your feedback
Your comment type
Submit
Azthena logo

AZoM.com powered by Azthena AI

Your AI Assistant finding answers from trusted AZoM content

Azthena logo with the word Azthena

Your AI Powered Scientific Assistant

Hi, I'm Azthena, you can trust me to find commercial scientific answers from AZoNetwork.com.

A few things you need to know before we start. Please read and accept to continue.

  • Use of “Azthena” is subject to the terms and conditions of use as set out by OpenAI.
  • Content provided on any AZoNetwork sites are subject to the site Terms & Conditions and Privacy Policy.
  • Large Language Models can make mistakes. Consider checking important information.

Great. Ask your question.

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.