Ultraviolet light emitting device incorporating optically absorbing layers
View Patent ↗A light emitting device includes a p-side, an n-side, and an active layer between the p-side and the n-side. The p-side includes a p-side contact, an electron blocking layer, a p-side separate confinement heterostructure (p-SCH), and a p-cladding/current spreading region disposed between the p-SCH and the p-side contact. The n-side includes an n-side contact, and an n-side separate confinement heterostructure (n-SCH). The active layer is configured to emit light in a wavelength range, wherein the p-side and the n-side have asymmetrical optical transmission properties with respect to the wavelength range emitted by the active layer.
1. A method comprising:
generating light in an active region of a light emitting device;
emitting the light toward a p-side of the device and toward an n-side of the device, wherein the p-side of the device includes a p-cladding/current spreading region and a p-side separate confinement heterostructure (p-SCH) disposed between the active layer and the p-cladding/current spreading region;
absorbing the majority of the light emitted toward the p-side of the device in the p-SCH; and
transmitting a majority of the light emitted toward the n-side of the device through the n-side of the device.
2. A method, comprising:
forming a n-side separate confinement heterostructure (n-SCH);
forming a light emitting active region, the active region comprising Al x Ga 1-x N;
forming a p-cladding/current spreading region adjacent a p-contact of the device; and
forming a p-side separate confinement heterostructure (p-SCH) comprising Al y Ga 1-y N, disposed between the active region and the p-cladding/current spreading region, wherein x>y.
3. The method of claim 2 , wherein forming the p-cladding/current spreading region comprises forming the p-cladding/current spreading region to have an Al concentration gradient.
4. The method of claim 2 , wherein forming the p-cladding/current spreading region comprises growing a superlattice having a predetermined number of layer pairs, each layer pair having a first layer and a second layer, wherein an Al concentration of one or both of the first layer and the second layer is a function of position in the superlattice.
5. The method of claim 2 , wherein forming the p-cladding/current spreading region comprises growing a superlattice having a predetermined number of layer pairs, each layer pair having a first layer and a second layer, wherein a thickness of one or both of the first layer and the second layer is a function of position in the superlattice.
6. The method of claim 2 , wherein forming the p-SCH comprises forming the p-SCH to be substantially optically absorbing at a wavelength range of light emitted by the active region.
7. The method of claim 6 , wherein the wavelength range of light emitted by the active region has a peak value less than about 300 nm.
8. The method of claim 2 , wherein:
forming the n-SCH comprises forming the n-SCH to be substantially optically transmissive at a wavelength range of light emitted by the active region; and
forming the p-SCH comprises forming the p-SCH to be substantially optically absorbing at the wavelength range of light emitted by the active region.