Demonstration of GaSb QW-based "Buffer-Free" LED on GaAs Substrate

The narrow band-gap III-Sb material system provides an excellent platform for development of infrared light emitters in the 1.55 to 5 ptm wavelength range. While high performance edge emitters have been demonstrated on GaSb substrates, similar success has not been seen with Sbbased Vertical-Cavity Surface-Emitting Lasers (VCSELs) due to the lack of a low-loss current and mode aperture that has been key to the success of As-based VCSELs. In this abstract we demonstrate a technology for development of Sb-based active regions on GaAs substrates using an interfacial misfit (IMF) dislocation array based nucleation, resulting in a "buffer-free" technology. The demonstrated device is an LED emitting vertically at 1.65 pIm with its DBRs grown directly on the GaAs substrate, without the use of any metamorphic buffers. The approach promises future devices such as VCSELs that may consist of arsenic based DBRs and Sb based active regions thus utilizing the long-wavelength Sb active regions while also incorporating the mature processing and manufacturing technology of GaAs. The scope of the technology is not restricted to GaAs substrates as has been shown by previously demonstrated results of optically pumped GaSb/Si VCSELs.1