Vertical cavity top-surface emitting lasers with thin Ag mirrors and hybrid reflectors

Abstract Three types of vertical cavity surface emitting lasers based on GaAs/AlGaAs have been grown by molecular beam epitaxy (MBE). The laser structures with top emission have been evolved from a simple double heterostructure (DH) with n-type distributed Bragg reflectors (DBR) as the bottom mirror and a semitransparent Ag as the top mirror, to a DH structure with a hybrid reflector consisting of a thin metal and a few pairs of p-DBR as the top mirror, and to a 3-QW structure again with a hybrid reflector as the top mirror. MBE growth of these three device structures is discussed, particularly on the in-situ growth of metals on GaAs. Devices have been fabricated and measured. A theoretical model has been used to gain an understanding of the parameters in each design. The MBE growth techniques have been improved to modify the heterostructural interface in the DBR to reduce the series resistance. The laser performance has been improved from a high threshold current in the first structure to a much lower threshold current in the second structure and finally to a cw room temperature operation with low threshold currents in the third structure.