Light emitting device
AssigneeRCA Corporation
InventorsGregory H. Olsen, Dan Botez
Life of this patent
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Abstract
A light emitting device comprises a substrate, a first confining layer overlying the substrate, an active layer overlying the first confining layer, a second confining layer overlying the active layer and a capping layer overlying the second confining layer. The improvement is the interposition of an absorber layer which absorbs light at the wavelength of the emission between the substrate and the first confining layer and a capping layer which absorbs light at the wavelength of the emission. The improved device exhibits an output beam which has a narrow angular intensity pattern in the plane perpendicular to the plane of the layers and to the end surfaces of the device.
Claims9
In a light emitting device comprising:
- a semiconductor substrate having two major surfaces;
- a first confining layer, overlying a first major surface of the substrate;
- an active layer overlying the first confining layer;
- a second confining layer overlying the active layer;
- a capping layer overlying the second confining layer;
- an electrical isolation layer overlying the capping layer and having an opening therethrough wherein the capping layer is exposed;
- an electrically conducting layer overlying the capping layer in the opening in the isolation layer whereby electrical contact is made to the capping layer;
- and
- an electrically conducting layer overlying the second major surface of the substrate whereby electrical contact is made to the substrate;
- wherein the substrate and the first confining layer are of one conductivity type and the second confining layer and the capping layer are of the opposite conductivity type;
- and
- wherein the substrate and the first and second confining layers are composed of a material transparent at the wavelength of a light beam emitted by the device;
- the improvement which comprises:
- an absorber layer composed of a material which is absorptive of light at the emitted wavelength interposed between the substrate and the first confining layer and of the same conductivity type as the substrate;
- and wherein the capping layer is absorptive of light at the emitted wavelength.
A light emitting device which comprises:
- a substrate composed of InP and having two major surfaces;
- an absorber layer overlying a major surface of the substrate, composed of an InGaAs alloy;
- a first confining layer, overlying the absorber layer, composed of InP;
- an active layer, overlying the first confining layer, composed of an InGaAsP alloy;
- a second confining layer, overlying the active layer, composed of InP;
- a capping layer, overlying the second confining layer, composed of an InGaAs alloy;
- an electrical isolation layer overlying the capping layer and having an opening therethrough wherein the capping layer is exposed;
- an electrically conducting layer overlying the capping layer in the opening in the isolation layer whereby electrical contact is made to the capping layer;
- and
- an electrically conducting layer overlying the second major surface of the substrate whereby electrical contact is made to the substrate;
- wherein the substrate, the absorber and the first confining layers are of one conductivity type and the second confining layer and the capping layer are of the opposite conductivity type;
- and
- wherein the substrate and the first and second confining layers are transparent at the wavelength of a light beam emitted by the device and the absorber and capping layers are absorptive of light at this wavelength.
Dependencies are inferred from the claim text.