A novel electrical and optical confinement scheme for surface emitting optoelectronic devices

摘要

A novel electrical and optical confinement scheme for surface emitting optoelectronic devices is presented. The scheme is based on epitaxial regrowth of a pnp current blocking layer structure around a mesa etched in the vertical cavity region of the device. The lateral size and orientation of the mesa is defined lithographically and dry etching is used to create vertical mesa sidewalls. By orienting the mesa sidewalls in certain crystallographic directions, it is possible to selectively grow a current blocking pnp layer structure on the exposed n-type lower cladding layer of the cavity whithout obstructing the electrical injection into the active region. The concept is evaluated in 1.2-μm GaAs-based light emitting diodes with InGaAs quantum wells. This type of structure can easily be used as the amplifying region of a vertical cavity laser, providing a good alternative to selective oxidation confinement.