DOUBLE HETEROSTRUCTURE LASER

摘要

1461632 Semi-conductor lasers MATSUSHITA ELECTRONICS CORP 26 Feb 1974 [26 Feb 1973 (2)] 8651/74 Headings H1C and H1K [Also in Division C4] A double heterostructure laser comprises, in sequence, a substrate, a Ga 1-y Al y As region of a first conductivity type, an active region, and a Ga 1-y Al y region of a second conductivity type, the proportions of either the substrate constituents or the constituents of one or more of the regions being chosen such that either the lattice constants of the substrate and adjacent region substantially coincide, or the lattice constant of the active region is smaller than that of the regions immediately adjacent. By avoiding lattice constant mismatching, fewer lattice dislocations forming non-radiative centres are obtained at the heteroboundaries and the threshold current for laser operation is lowered. Lattice constants of substrate and adjacent region are subsequentially coincident. The semiconductor laser of Fig. 2 is formed by epitaxial growth of an N-type region 12, a GaAs active region 13, a P-type region 14 and a P-type GaAs region on an N-type Ga 1-x In x As substrate. Both regions 12 and 14 comprise The value of x in the substrate constituents is selected from the range 0À025#x>0 for lattice constant coincidence. The structure includes electrodes 111, 16 and a cleaved end surface 1111. Lattice constant of active region smaller than that of immediately adjacent regions. The regions of this laser, Fig. 3, differ from Fig. 2 in that the substrate 21 is N-type GaAs and the active region 23 is Ga 1-z In z As, where 0À015>z >0.