Researchers from ARC's Center of Excellence for Transformative Elemental Optical Systems (TMOS) have developed a novel approach to on-chip light source engineering, which is expected to drive the widespread adoption of photonic chips in consumer electronics. In the recent issue of the journal Light: Science and Applications, a team of researchers from the National University of Australia and collaborators from Northwestern Polytechnical University describe a method for growing high-quality multi-quantum well nanowires using indium gallium arsenide and indium phosphide semiconductor materials.
Optical information transmission is far superior to traditional electrical signal transmission in terms of speed and efficiency, which is the main reason for the rapid development of the photonic chip industry in the past decade. Currently, photonic chips (also known as photonic integrated circuits) are widely used in consumer devices such as telecommunications equipment, autonomous vehicles, biosensors, and smartphones. However, a major challenge facing current photonic chips is the lack of on-chip light sources, which forces them to rely on external light sources, limiting the miniaturization potential of the chips and their devices.
Nanowire lasers are considered ideal candidates for on-chip light sources, but large-scale fabrication of high-quality nanowires operating at room temperature with smooth sidewalls, controlled size, and precise crystal composition has been a technical challenge. In response, TMOS researchers and collaborators have developed an innovative multi-step surface engineering approach that uses selective regiotaxy metal-organic chemical vapor deposition to achieve nanowire growth.
Figure: New advances in photonic chips will open up an industry
"With this new epitaxial growth technique, we are able to precisely control the diameter and length of quantum well nanowires, while ensuring high crystal quality and uniform morphology," said Fanlu Zhang, a PhD student at TMOS and co-first author. This allows us to design tunable nanowire optical cavities that can be adjusted in both spatial and longitudinal modes. By varying the composition and thickness of quantum wells, we are also able to adjust the laser wavelength of the nanowires to cover a broad spectrum of near-infrared telecommunication bands.”
Xutao Zhang, another co-first author, added: "Our technology is well suited for the large-scale production of homogeneous nanowire arrays, which will enable high-volume manufacturing of nanoscale laser light sources in the near-infrared telecommunication band. This approach is expected to overcome the traditional technical barriers to fabricating on-chip light sources by bonding or heteroepitaxy, paving the way for large-scale photonic integration.”
Lan Fu, Principal Investigator at TMOS, emphasized: "This marks an important advance in on-chip light source technology and the photonic chip industry, especially providing the basis for the mass production of these devices. The next research focus will be on the design and fabrication of electrical contacts to realize the possibility of electrically injected lasers.”
