Fabrication challenges of electrical injection metallic cavity semiconductor nanolasers

The recently emerged metallic-cavity nanolasers have opened a new phase of miniaturization of semiconductor lasers down to sub-wavelength scale. This new type of semiconductor lasers is suitable for many low-power applications due to its small size, tight optical confinement and good heat dissipation. However, there are major technical challenges in the fabrication of such nanolasers that must be overcome to make high-quality devices with high yield needed for practical applications. Here we will discuss several fabrication issues that are critical to the device performance. These issues, including device patterning, pillar etching, surface passivation and metal deposition, will determine both optical and electrical properties, especially the lifetime, threshold, and efficiency of a nanolaser.