The Need

The continued push for high speed, low power, and compact solutions has given rise to the field of integrated optics/photonics, which aims to combine the high bandwidth and low loss transmission of fiber optic technology with the large device density and high production volume of modern microelectronics. Silicon is one of the most widely used materials for integrated optics due to its high index contrast with SiO₂, low material absorption in the fiber optic communication bands (1260 – 1660 nm wavelength), and compatibility with complementary metal oxide semiconductor (CMOS) processing. However, relatively little progress has been made towards an electrically driven silicon-based light source, a fundamental device required for fully functional photonic circuits. Silicon’s crystal structure contributes to this problem, which results in an indirect bandgap and a low radiative efficiency. Additionally, light emitted by the bandgap transition (~1100 nm wavelength) is outside the fiber optic communication window, and is within silicon’s absorption band which is not suitable for on chip signal routing. Thus, there is a need for an efficient silicon based light emitter in the sub-bandgap 1260 – 1660 nm range.

The Technology

Researchers at The Ohio State University, led by Dr. Ronald Reano, have developed a novel thin film material in the form of hydrogenated amorphous silicon (aSi:H), which demonstrates sub-bandgap light emission. The electrically pumped aSi:H based light emitters are able to provide optical power to integrated photonic circuits at telecommunications wavelengths and are CMOS compatible. The researchers have demonstrated photoluminescence enhanced by the Purcell Factor in aSi:H ring resonantors. This technology paves the way for very large scale integration and high volume manufacturing.

Commercial Applications

• Photonic Chip Fabrication
• IT and Telecommunications Materials
• High Performance Data Centers
• Photonic Computing
• Optical Fiber Communication Equipment

Benefits/Advantages

• Maintains large refractive index contrast with SiO₂
• CMOS compatible
• Enhanced photoluminescence across the 1300 nm - 1600 nm wavelength range, compared to c-Si devices
• Allows for very large scale integration and high volume manufacturing that come from using a unified material platform