Stimulated Emission and Laser Operation (cw, 77°K) of Direct and Indirect GaAs1−xPx on Nitrogen Isoelectronic Trap Transitions

The various factors governing the laser operation of direct and indirect semiconductors on isoelectronic trap transitions are considered. A detailed description is given of the operation of optically pumped GaAs1−xPx:N lasers, and the simple and compound optical cavities used for this purpose. The laser operation (cw, 77°K) of direct and indirect GaAs1−xPx:N (0.32≤x≤0.60) on nitrogen-trap transitions is described. Stimulated emission characteristic of an inhomogeneously broadened line is shown to occur on NN pair transitions, both in direct and indirect crystals. Laser operation more characteristic of a homogeneously broadened line is observed on nitrogen A-line transitions, depending to some extent, however, on the crystal composition and the depth of the trap relative to the conduction band.