Buried tunnel contact junction AlGaAs-GaAs-InGaAs quantum well heterostructure lasers with oxide-defined lateral currents

Al x Ga 1−x As-GaAs-In y Ga 1−y As quantum well heterostructure (QWH) lasers with p+-n+ GaAs–InyGa1−yAs reverse-biased tunnel junctions (hole sources) located in the upper cladding of standard lasers and in oxide-defined cavities (requiring lateral bias currents) are demonstrated. The tunnel junctions, introduced to aid lateral current spreading, are grown at different distances from the waveguide active region in a standard QWH structure to determine first the effect of heavily doped tunnel layers on laser threshold currents. Other QWH laser crystals are oxidized to form oxide-aperture devices with, in addition, either a top confining oxide or a top and bottom oxide confining layer. Hole injection is provided between the oxide layers with the aid of the tunnel contact junction and lateral electron current. The buried tunnel contact junction is shown to be an effective method to make possible hole injection via a lateral electron current, with only a modest increase (a small penalty) in voltage drop and series resistance compared to standard devices.