Transverse light emitting electroluminescent devices
AssigneeXerox Corporation
InventorsRobert D. Burnham, Donald R. Scifres, William Streifer
Life of this patent
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Abstract
Improved lateral carrier and optical confinement is achieved in heterostructure diodes and lasers having a Fabry-Perot cavity transverse to the plane of the p-n junction of the device. Structural features during fabrication improve carrier confinement to the active region in the established optical cavity. Current confinement means is also fabricated above and below the active region to concentrate the current density to the active region in the optical cavity and thereby improve the overall gain of the device. Such confinement also enhances optical confinement along the cavity. Several reflector structures are disclosed for employment at the cavity ends to provide optical feedback.
Claims21
In a transverse radiation emitting semiconductor electroluminescent device wherein optical wave propagation is in a direction transverse to the planar deposition of a plurality of contiguous semiconductor layers comprising said device, one of said layers forming an active layer and having an active region with a p-n junction thereat, means to establish a transverse optical cavity for supporting optical wave propagation under lasing conditions in a direction transverse to the planar extent of said active layer when a current is applied across said junction, the emission of radiation from said device being from at least one end surface thereof transverse to the planar extent of said layers and at one end of said transverse optical cavity, current confinement means in said device to aid in the confinement of current to said active region, said device characterized by
- transverse waveguide confinement means surrounding at least a portion of said transverse optical cavity and extending in a direction parallel to said cavity through and beyond the lateral boundaries of said active region, the semiconductor compositional materials comprising said waveguide confinement means having a bandgap and refractive index, respectively, wider and lower than the material comprising said active region.
In a transverse radiation emitting semiconductor electroluminescent device wherein optical wave propagation is in a direction transverse to the planar deposition of a plurality of of a contiguous semiconductor layers comprising said device, one of said layers forming an active layer and having an active region with a p-n junction thereat, means to establish a transverse optical cavity for supporting optical wave propagation under lasing conditions in a direction transverse to the planar extent of said active layer and region when a current is applied across said junction, the emission of radiation from said device being form at least one end surface thereof transverse to the planar extent of said layers and at one end of said transverse optical cavity, said device characterized in that
- said transverse optical cavity extends in a direction parallel to said cavity through and beyond the lateral boundaries of said active region and is formed from different compositions of semiconductor materials than regions outside of said transverse optical cavity such that the active region and regions of said layers within said transverse optical cavity immediately adjacent to said active layer have a lower bandgap and higher index of refraction than respective regions of these layers outside of said transverse optical cavity.
Dependencies are inferred from the claim text.