UNIQUE TOP-DRIVEN LOW-THRESHOLD LASERS BY IMPURITY-INDUCED DISORDERING

We have made top-driven lasers by impurity-induced disordering (IID). Compares with conventional top-driven lasers, that is, transverse-junc tion-stripe (TJS) lasers, the top-driven IID (TID) lasers are unique i n that the carriers in the active quantum-well stripe are injected ver tically from (instead of laterally between) the cladding layers of the lasers. Because the vertical injection is much more efficient than th e lateral injection, the threshold current of the TID lasers is lower than that of TJS lasers by a factor of 2-10. The lowest threshold curr ent observed for the TID lasers was I(th) = 1.6 mA under room-temperat ure continuous-wave operation. By having proper material design and de vice processing, the top n-type contact of the TID lasers is obtained virtually as good as the bottom n-type contact of conventional IID las ers.