Light emitting diodes with aluminum-containing layers integrated therein and associated methods
A light-emitting diode (LED) structure includes an active region that has at least one aluminum-containing quantum well (QW) stack that emits light from the LED structure when activated. The LED structure exhibits a modified internal quantum efficiency value, which is higher than a LED structure that does not include aluminum within a QW stack. The LED structure also exhibits a modified peak wavelength, which is longer than an unmodified peak wavelength of the unmodified LED structure.
1 . A light-emitting device comprising:
a semiconductor substrate; and
a red light-emitting diode (LED) structure, including:
an active region disposed on the semiconductor substrate, the active region including:
a first barrier layer;
a first aluminum gallium nitride (AlGaN) layer formed on the first barrier layer;
a quantum well (QW) formed on the first AlGaN layer;
a second AlGaN layer formed on the QW;
a second barrier layer; and
a p-doped layer formed on the active region,
the QW being configured to emit red light during electrical operation of the light-emitting device.
2 . The light-emitting device of claim 1 , wherein the red light has a wavelength in a range 610-760 nanometer.
3 . The light-emitting device of claim 1 , wherein the QW includes indium gallium nitride (InGaN).
4 . The light-emitting device of claim 1 , wherein the QW includes aluminum indium gallium nitride (AlInGaN).
5 . The light-emitting device of claim 4 , wherein the AlInGaN has an Al composition in a range 0.01% to 5%.
6 . The light-emitting device of claim 1 , wherein;
the first barrier layer is a first gallium nitride (GaN) layer; and
the second barrier layer is a second GaN layer.
7 . The light-emitting device of claim 1 , further comprising a green LED structure and a blue LED structure are monolithically formed with the red LED structure on the semiconductor substrate.
8 . The light-emitting device of claim 1 , wherein the active region includes more than four QWs.
9 . The light-emitting device of claim 1 , further comprising a preparation layer disposed between the semiconductor substrate and the first barrier layer.
10 . The light-emitting device of claim 9 , wherein the preparation layer includes indium gallium nitride (InGaN) and does not emit visible light during electrical operation of the light-emitting device.
11 . The light-emitting device of claim 1 , wherein the red LED structure has a lateral dimension between 1 micrometer (μm) and 10 μm.
12 . The light-emitting device of claim 1 , wherein the first AlGaN layer and the second AlGaN layer have respective Al compositions in a range 5%-100%.
13 . The light-emitting device of claim 1 , wherein the QW is in direct contact with the first AlGaN layer and the second AlGaN layer.
14 . The light-emitting device of claim 1 , wherein the QW is separated from the first AlGaN layer by a spacer layer including gallium nitride (GaN).
15 . The light-emitting device of claim 1 , wherein the active region is a periodic stack, a period of the periodic stack including the first barrier layer, the first AlGaN layer, the QW, the second AlGaN layer, and the second barrier layer.
16 . A monolithic light-emitting diode (LED) device comprising:
a semiconductor substrate; and
a red LED structure, a green LED structure, and a blue LED structure formed monolithically on the semiconductor substrate, and respectively emitting red light, blue light and green light during electrical operation of the monolithic LED device,
the red LED structure including:
an active region disposed on the semiconductor substrate, the active region including:
a first barrier layer;
a first aluminum gallium nitride (AlGaN) layer formed on the first barrier layer;
a quantum well (QW) formed on the first AlGaN layer;
a second AlGaN layer formed on the QW; and
a second barrier layer; and
a p-doped layer disposed on the active region.
17 . The monolithic LED device of claim 16 , wherein the QW includes aluminum indium gallium nitride (AlInGaN) with an Al composition in a range 0.01% to 5%.
18 . The monolithic LED device of claim 16 , further comprising a preparation layer disposed between the semiconductor substrate and the first barrier layer, wherein the preparation layer includes indium gallium nitride (InGaN) and does not emit visible light during electrical operation of the monolithic LED device.
19 . A method of forming a light-emitting diode (LED) structure comprising:
growing an active region on a substrate, the active region including:
a barrier layer;
a first layer formed on the barrier layer;
a quantum well (QW) formed on the first layer; and
a second layer formed on the QW;
incorporating Al in at least one of:
the first layer,
the QW, or
the second layer; and
growing a p-doped layer on the active region,
the QW being configured to emit red light under electrical operation of the LED structure.
20 . The method of claim 19 , wherein the QW includes aluminum indium gallium nitride (AlInGaN) with an Al composition in a range 0.01% to 5%.
21 . The method of claim 19 , further comprising forming a preparation layer disposed between the substrate and the barrier layer, wherein the preparation layer includes indium gallium nitride (InGaN) and does not emit visible light during electrical operation of the LED structure.