Blue and green vertical cavity surface emitting lasers (VCSELs) are expected to be used in future generation display and lighting applications. Applications in virtual reality (VR), augmented reality (AR), retinal scanning display (RSD), and portable projection devices are only a few of the anticipated applications. However, in spite of vigorous pursuit for more than two decades, GaN VCSELs have yet reached commercialization.
The main challenge in the technology of III-nitride VCSELs is the fabrication of distributed Bragg reflectors (DBRs) that can provide near-unity reflection and thus support the formation of high-quality vertical cavity. Several groups reported VCSEL operations using epitaxial DBRs (using AlGaN/GaN or AlInN/GaN) and dielectric DBRs (involving lift-offs or epitaxial lateral overgrowth). In this talk, we will discuss an alternative approach to this challenging problem by using electrochemistry to create nanoporous GaN as a low-index medium, toward a manufacturable DBR mirror technology to support blue and green VCSELs. This nano-engineering based on electrochemistry can help to circumvent impasses and creates new dimensions in the exploration of optoelectronic devices using GaN.
We acknowledge research support from US Department of Energy, National Science Foundation, DARPA, and IP Group.