Irish researcher designs pyramid-shaped quantum dot LED

Giant companies such as Google, Intel and IBM have invested millions in quantum computing, an innovative technology widely considered to be the next generation of global computing, which will enable faster and more efficient processing to cater for future computing, high-speed networks, data encryption and other applications such as defense, security, sensing, etc.

Recently, researchers at Tyndall National Institute in Ireland used a scalable and foundry-compatible lithography process to design a pyramid-shaped quantum dot light-emitting diode (LED), which is expected to generate entangled photons associated with action and state for quantum computing.

Project leader Dr. Emanuele Pelucchi said that this research may be used in quantum computing research in the future to accelerate the application of quantum technology.

The Tyndall Institute used nanotechnology to electrify a pyramid-shaped array of quantum dots to produce entangled photons. Taking advantage of the inherent nanoscale properties of the pyramidal structure, especially for engineered, self-assembled vertical quantum wires, it is possible to selectively inject current into the quantum dots. The results reported in the article are an important step towards realizing the design of quantum photonic integrated circuits, laying the foundation for thousands or more quantum information processing tasks running simultaneously.

By etching back the original substrate, the researchers restored it to a pyramid structure with the top upward, thereby improving light capture by several orders of magnitude compared to embedded components built in-house. The top and bottom contacts are then designed to selectively inject current into individual QDs in the center of the pyramid structure. The key is to use self-calibration techniques to make the device easy to manufacture at scale.

By accessing all of the μLEDs, the researchers were able to perform extensive analysis on approximately 1,300 μLEDs, but also plan to control the μLEDs individually for better performance selectivity and to compensate for process non-uniformity.

Ideally, for quantum information processing, researchers would like to use μLEDs as completely indistinguishable sources of entangled photons. The photon capture efficiency is also quite low, around 1%, so the researchers hope to improve it by using different techniques, such as stress and electric fields in the built-in materials. Researchers at Tyndall have developed plans for quantum dot light-emitting diodes that can produce entangled photons, which could theoretically be used to encode information in quantum computing. Pelucchi explained that this is not the only way to generate entangled photons in LEDs, but as described in the Nature Photonics article, the method and materials have important implications for the future of quantum technology.

While traditional digital computing relies on binary switches, quantum computing exploits the quantum state of an event—such as entangled photons or the multiple states of an atom—to encode information. In theory, this could lead to faster and more powerful computer processing, but current technology cannot support large-scale development.

Scalable electric quantum dot array, this innovation uses easily available materials and traditional semiconductor manufacturing techniques. This method can achieve direct acquisition of the position of the entangled photon source. The key technology lies in the position control and manufacturing technology of quantum dots. Their development will promote the wider use of quantum computing technology.