A simple and versatile technique for manufacturing hybrid lasers on different materials opens the door to new applications for photonic devices.
Fabricating hybrid semiconductor lasers on materials other than the commonly used silicon-on-insulator (SOI) substrates has proved challenging. Now, A*STAR researchers have developed an innovative technique that can integrate the lasers on to a range of different materials.
Schematic of the hybrid laser
© 2017 A*STAR Data Storage Institute
Hybrid lasers combine the light-emitting properties of group III-V semiconductors like gallium arsenide and indium phosphide, with conventional silicon technologies, offering inexpensive photonic and microelectronic devices for application in optical telecommunication systems.
Their range of applications, however, is limited by the poor light-emitting characteristics of the silicon-on-insulator (SOI) wafers mostly used as substrates in the fabrication process. This spurred Doris Keh-Ting Ng and colleagues from the A*STAR Data Storage Institute to develop an innovative technique for bonding III-V lasers on to other substrates, be it silicon, quartz, or metal alloys.
By using an ultrathin layer of silicon oxide to bond the lasers to a silicon substrate, the researchers developed a simpler, safer and more flexible technique than direct bonding, which relies on chemical bonding between the surfaces.
“The challenge is to produce a smooth, extremely thin layer of silicon oxide on the surface of the substrate,” explains Ng. “By growing the film on the silicon substrate, but not on the III-V substrate, we greatly reduced the complexity of the process and improved the strength of the bond between the two materials.”
After first cleaning the surfaces with an organic solvent, the researchers exposed the surface to an oxygen plasma to increase its adhesive properties. They then initiated the bonding process at ambient temperature by bringing the two substrates slowly together, to reduce the air trapped between them, ensuring a much stronger bond.
The bonding was then completed at relatively low temperatures of around 220 degrees Celsius, allowing the ultrathin layer of silicon oxide to conduct heat between the layers, reducing potential damage to the materials, strengthening the bond and avoiding the need for hazardous chemicals, such as Piranha solution and hydrofluoric acid, used in direct bonding.
The work demonstrates a versatile on-chip laser that can be integrated on to any material platform and could lead to new applications for photonic devices, such as detector-on-chip and modulator-on-chip technologies.
“The low temperature interlayer approach is simpler and much safer than direct bonding, and means that laser manufacturers are not restricted by the choice of substrate,” says Ng.
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute.
 Lee, C. W., Ng, D. K. T., Ren, M., Fu, Y. H., Kay, A. Y .S. et al. Generic heterogeneously integrated III–V lasers-on-chip with metal-coated etched-mirror. IEEE Journal of Selected Topics in Quantum Electronics 22, 1500409 (2016).
A*STAR Research | asia-Research News
MEMS chips get metatlenses
21.02.2018 | American Institute of Physics
International team publishes roadmap to enhance radioresistance for space colonization
21.02.2018 | Biogerontology Research Foundation
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences