Light emitting devices and method of manufacture

Abstract

A light emitting device including an N-polar semiconductor nanowire region having a first doping type. An indium gallium nitride / gallium nitride (InGaN / GaN) N-polar short period superlattice (SPSL) region of each nanowire, having a fist doping type, can be disposed on the N-polar semiconductor region. An indium gallium nitride (InGaN) N-polar single-segment (SS) active region of each nanowire can be disposed on the InGaN / GaN N-polar short period superlattice (SPSL) region opposite the N-polar semiconductor region. A tunnel junction region of each nanowire, having a second doping type, can be disposed on the InGaN N-polar single-segment (SS) active region opposite the InGaN / GaN N-polar short period superlattice (SPSL) region.

Description

Light Emitting Devices and Methods of ManufactureCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. filed , which is incorporated herein in its entirety.BACKGROUND OF THE INVENTION

[0002] Light emitting devices utilizing group Ill-nitride semiconductors are currently under rapid development for next-generation high-resolution and high-brightness displays, augmented / virtual reality (AR / VR) technologies, and the like. However, it remains elusive to achieve red-emitting Ill-nitride micro-LEDs with microscale size, high efficiency and spectral stability, which poses significant impediments to the development of full-color micro-LEDs.

[0003] Light-emitting diodes (LEDs) with characteristic length scales on the order of microns or less, also known as micro-LEDs, have been under investigations over the past two decades for their promise in various display and communications scenarios, such as lightweight self- powered wearable displays with resolutions on the level of human eyes' visible light, communications, ultrahigh-speed optical interconnects, sensors and biomedical probes. Among the many material systems investigated for mini- and micro-LEDs, including I ll-phosphides, Ill- nitrides, I l-VI, and perovskites, as summarized in Table 1, indium gallium nitride (InGaN) has been the predominant material system of choice, due to desirable properties such as comparatively low surface recombination velocities, excellent wavelength tunability, and the potential for monolithic integration of red, green, and blue LEDs, which is particularly important for full-color displays. However, there remains a need for high efficiency red micro-LEDs.Table 1SUMMARY OF THE INVENTION

[0001] The present technology may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the present technology directed toward a red-light emitting nanowire devices.

[0002] In one embodiment, a light emitting device can include one or more nanowires. Each nanowire can include an N-polar semiconductor region having a first doping type. An indium gallium nitride / gallium nitride (InGaN / GaN) N-polar short period superlattice (SPSL) region of each nanowire, having a fist doping type, can be disposed on the N-polar semiconductor region. An indium gallium nitride (InGaN) N-polar single-segment (SS) active region of each nanowire can be disposed on the InGaN / GaN N-polar short period superlattice (SPSL) region opposite the N-polar semiconductor region. A tunnel junction region of each nanowire, having a second doping type, can be disposed on the InGaN N-polar single-segment (SS) active region opposite the InGaN / GaN N-polar short period superlattice (SPSL) region.

[0003] In another implementation, a method of fabrication a light emitting device can include expitaxia lly depositing an N-polar indium gallium nitride / gallium nitride (InGaN / GaN) short period superlattice (SPSL) nanowire region having a first doping type on a N-polar semiconductor nanowire region having the first doping type. An N-polar indium gallium nitride (InGaN) single-segment (SS) active nanowire region can be epitaxially deposited on the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region opposite the N-polarsemiconductor nanowire region. A tunnel junction nanowire region, having a second doping type, can be epitaxially deposited on the N-polar InGaN N-polar single-segment (SS) active nanowire region opposite the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region.BRIEF DESCRIPTION OF DRAWINGS

[0004] Embodiments of the present technology are illustrated by way of example and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0005] FIGS. 1A and IB show a comparison of micro-LEDs operating parameters, for the conventional art compared to an embodiment in accordance with aspects of the present technology.

[0006] FIGS. 2A-2H show a comparison between structures with and without a short period superlattice (SPS) region beneath an InGaN single-segment (SS) active region, in accordance with aspects of the present technology.

[0007] FIGS. 3A-3D show a device with an n-GaN spacer between a short-period superlattice (SPS) region and an active region, and associated operating parameters, in accordance with aspects of the present technology.

[0008] FIGS. 4A and 4B show performance parameters of another light emitting device, in accordance with aspects of the present technology.

[0009] FIGS. 5A and 5B show energy band structures and carrier concentrations of devices with and without an n-GaN interlayer between a short period superlattice (SPS) region and a singlesegment (SS) active region, in accordance with aspects of the present technology.DETAILED DESCRIPTION OF THE INVENTION

[0010] Reference will now be made in detail to the embodiments of the present technology, examples of which are illustrated in the accompanying drawings. While the present technology will be described in conjunction with these embodiments, it will be understood that they are not intended to limit the technology to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present technology, numerous specific details are set forth in order to provide a thorough understanding of the present technology. However, it is understood thatthe present technology may be practiced without these specific details. In other instances, well- known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present technology.

[0011] The present technology may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the present technology directed toward micro and nano-scale light emitting devices emitting in the red light spectrum. Through detailed strain engineering and control of charge carrier transport, embodiments of the present technology achieved red emission (>620 nm) micro-LEDs having an injection current range of over two orders of magnitude of variation. In embodiments, the combination of a short-period indium gallium nitride / gallium nitride (InGaN / GaN) superlattice and a thick n-type GaN interlayer can not only relieve the quantum-confined Stark effect but also enhance the electron-hole overlap in the active region. The deep red micro-LEDs embodiments can achieve external quantum efficiency over 3% emitting at approximately 660 nm.

[0012] Recently, InGaN-based micro-LEDs with micron and sub-micron scale and external quantum efficiency (EQE) of greater than 20 percent ( >20%) have been reported in the blue and green wavelengths. Referring now to FIGS. 1A and IB, a comparison of operating parameters of micro-LEDs is shown. FIG. 1A shows a device length versus peak external quantum efficiency (EQE) for various recent ultra-small red (peak emission greater than 620 nm) LEDs in the current literature. In addition, the corresponding device length versus peak external quantum efficiency (EQE) for a device in accordance with aspects of the present technology is shown by the star. FIG. IB shows a comparison of normalized current versus wavelength for the various recent ultra-small red (peak emission greater than 620 nm) LEDs in the current literature. The normalized current versus wavelength for a device in accordance with aspects of the present technology is also shown. For each device collected in this figure, the current is normalized against the current injection level corresponding to the maximal external quantum efficiency.

[0013] InGaN-based red-emitting micro-LEDs have proved to be much more challenging, where the best reported EQE percentage values remain in the single digits. Despite various strategies, such as AIGaN interlayer and using patterned substrate, that have been utilized to relieve strain and thus enhance indium (In) incorporation to levels necessary for red emission, it has remained elusive to achieve high efficiency red micro-LEDs due to the lattice mismatch and the low intermiscibility between indium nitride ( InN) and gallium nitride (GaN) limiting the development of full-color micro-LED displays. Besides severely limiting the efficiency for red micro-LEDs, highlevels of strain in high indium InGaN generate a large piezoelectric field, which leads to significant blue shifts in emission wavelength with increasing carrier density in the active region. Compounded further by the quantum-confined Stark effect (QCSE) inevitable for all polar InGaN-based LEDs, which have demonstrated the highest efficiencies among all InGaN polarities, InGaN-based micro-LEDs targeting red emission so far still suffer greatly from device color instability under different operating conditions, as summarized in FIG. IB.

[0014] In accordance with embodiments of the present technology, InGaN micro-LEDs can be grown on N-polar GaN / sapphire substrates via plasma-assisted selective area molecular beam epitaxy (MBE). To achieve selective area epitaxy of nanowire arrays, approximately 10 nm of titanium can first be deposited on a GaN / sapphire substrate, and then patterned via electron beam lithography and reactive ion etching. After cleaning and loading into a MBE growth chamber, the patterned substrate can be nitridated at approximately 400 °C for approximately 10 minutes to suppress parasitic growth on the masked regions. The substrate temperature can then be ramped to approximately 940 °C for the growth of Si-doped n-GaN nanowire arrays as designed. In one implementation, the Si-doped n-GaN nanowire regions can be grown with an N-polar lattice. Following the n-GaN segment, InGaN-containing segments can be grown, which contain the red-emitting active region, and then various performance engineering layers to be discussed in detail below. Finally, a Mg-doped p-GaN segment can be deposited on top of the InGaN segments to complete the LED structures for the nanowire array.

[0015] Referring now to FIGS. 2A-2H, a comparison between structures with and without a short period superlattice (SPS) beneath an InGaN single-segment (SS) active region, in accordance with aspects of the present technology, is shown. FIG. 2A shows a diagram of a device without the InGaN single-segment (SS) active region. FIG. 2B shows a scan transmission electron microscope high angle annular dark-field (STEM-HAADF) image of a device without the InGaN single-segment (SS) active region. FIG. 2C shows a scan transmission electron microscope low angle annular dark-field (STEM-LAADF) image of the device without the InGaN single-segment (SS) active region. FIG. 2E shows a diagram of a device with the InGaN single-segment (SS) active region. FIG. 2F shows a STEM-HAADF image of a device with the InGaN single-segment (SS) active region. FIG. 2G shows a STEM-LAADF image of the device with the InGaN singlesegment (SS) active region. FIG. 2D shows a comparison of normalized intensity contrast between line scan shown in FIGS. 2B and 2F. FIG. 2H shows a comparison of photoluminescence spectrum between the device with and without the InGaN single-segment (SS) active region.

[0016] To achieve the indium incorporation levels required for red emission, prior to the growth of the active region, an InGaN / GaN short-period superlattice (SPS) with photoluminescence peak wavelengths typically in the range of 500 to 550 nm (corresponding to an indium composition of approximately 30% in the InGaN layers) can be employed, as shown in FIG. 2A. In one implementation, the short-period superlattice (SPS) can be Si-doped to improve electron injection efficiency into the active region. In one implementation, the short-period superlattice (SPSL) regions can be N-polar indium gallium nitride / gallium nitride (InGaN / GaN). A single, comparatively thick (approximately 20 nm) segment of N-polar InGaN can be formed for the red-emitting active region, as shown in FIG. 2A. FIG. 2B shows a high angle annular dark field (HAADF) image, taken with scanning transmission electron microscopy (STEM), of a LED nanowire with a single-segment N-polar InGaN active region. The single-segment InGaN is shown in the central region of the image with higher contrast intensities due to the higher atomic number of the InGaN region compared to the surrounding GaN layers. The corresponding low angle annular dark field (LAADF) image, in FIG. 2C, shows that there are high contrast brightness regions around the single-segment InGaN active region, indicating significant levels of strain both above and below the active region, as high levels of contrast brightness in LAADF for similar material are due to quasi-elastic scattering and de-channeling effects arising from strain-induced lattice distortion.

[0017] Referring now to FIGS. 2F and 2G, STEM-HAADF and LAADF images, respectively, of a LED nanowire with the short period superlattice (SPSL) beneath the active region are shown. In contrast to the nanowire with only a single-segment InGaN, as shown in FIG. 2C, which is the active region, the nanowire with the SPS beneath the single segment shows no significantly enhanced contrast intensity in or around the InGaN regions in the LAADF image, as shown in FIG. 2G, when compared to the top and bottom GaN regions. The comparison in contrast intensity between the two nanowire structures is highlighted in FIG. 2D, which shows the cutlines given by the arrows in FIGS. 2C and 2G, where the LAADF signal contrast intensity is respectively normalized against the contrast intensity in the bottom n-GaN regions, which are comparable between the two nanowire structures (i.e., with and without the SPS). From this normalized intensity comparison, it is evident that the level of strain around the active region for the nanowire with the SPS (blue curve) is significantly less than that without (red curve). In addition, the (normalized) contrast intensity in the InGaN single-segment active region itself is similarly lower with a SPS beneath than without, indicating that the SPS employed hereeffectively alleviates the strain in the (relatively) thick InGaN active region layer, which shows longer wavelength (629 nm vs 622 nm), and 1.8 times stronger photoluminescence as shown in FIG. 2H. It is worth noting that, for most GaN / lnGaN superlattices reported in the literature, which are planar device growths, the number of periods is greater than ten and the indium composition is less than 15%, while the short-period superlattice in accordance with aspects of the present technology, which effectively relaxes strain for the red-emitting active region in the nanowires, has just four periods and is approximate 30% in indium (In) composition. The combination of SPS and a single-segment InGaN active region reliably achieves photoluminescence with peak wavelengths longer than 620 nm, a commonly defined lower boundary of the red wavelength range, and the high optical quality necessary for high-efficiency devices.

[0018] As evident from the PL spectra in FIG. 2H, however, the SPS itself has green emission with peak intensities comparable to or even stronger than the red-emitting InGaN. Indeed, a significant blueshift for the device structure presented in FIG. 2E can be present at elevated carrier injection levels where electrons and holes radiatively recombine in the SPS. Referring now to FIGS. 3A-3D, a device with an n-GaN spacer between a short-period superlattice (SPS) region and an active region, and associated operating parameters, in accordance with aspects of the present technology, are shown. FIG. 3A shows a diagram of a device with an additional n- GaN spacer between a short-period superlattice (SPS) region and an active region. FIG. 3B shows an applied bias vis energy density (J-V) characteristic, with a scanning electron micrograph insert, of the device. FIG. 3C shows an energy density versus external quantum efficiency of the device. FIG. 3D shows a wavelength versus electroluminescence of the device.

[0019] A parasitic emission from the SPS can be quenched with the addition of a hole blocking n- doped gallium nitride (n-GaN) spacer layer between the InGaN active region and the SPS, as shown in FIG. 3A. In one implementation, the n-GaN spacer can have an N-polar lattice. In addition, an intrinsic gallium nitride (i-GaN) buffer layer can be disposed between the singlesegment (SS) active region and the n-GaN spacer layer. The i-GaN spacer can have an N-polar lattice. Referring now to FIG. 3B, the device's J-V characteristics is shown. With a peak external quantum efficiency of approximately 3.9%, as shown in FIG. 3C, emitting at 622 nm, the device emits at a 612 nm peak wavelength when driven with a current density ten times the peak EQE injection level, as shown in FIG. 3D. Referring now to FIGS. 4A and 4B show performance parameters of another light emitting device, in accordance with aspects of the presenttechnology. FIG. 4A shows an energy density versus wavelength characteristic for the device. FIG. 4B shows a wavelength versus electroluminescence intensity characteristic for the device.

[0020] Under slightly different growth conditions, the device emission wavelength can be tuned to remain red {i.e., with peak emission wavelength > 620 nm) over a wide range (two orders of magnitude variation) of current injection levels, as shown in FIGS. 4A and 4B. As shown in FIG. 4A, the electroluminescence (EL) peak wavelength remains longer than 620 nm over two orders of magnitude change in injected current density, with a peak EQE of about 3.3%. The full EL spectra are shown in FIG. 4B. As emission remains red over two orders of magnitude of current injection levels, the suppression of parasitic emission from the InGaN / GaN superlattice by the insertion of the hole blocking n-GaN interlayer between the InGaN active region and the SPS is confirmed, and the dynamic range of displays employing this micro-LED is guaranteed. For comparison, to the best of our knowledge, essentially all InGaN-based red micro-LEDs reported in the literature so far blueshift to orange wavelengths {<620 nm) at high levels of carrier injection in FIG. IB.

[0021] Referring now to FIGS. 5A and 5B, energy band structures and carrier concentrations of devices with and without an n-GaN interlayer between a short period superlattice (SPS) region and a single-segment (SS) active region, in accordance with aspects of the present technology, are shown. FIG. 5A shows a simulated energy band structure and carrier concentration of a device structure under 6V of forward bias with the n-GaN interlayer between a short period superlattice (SPS) region and a single-segment (SS) active region. FIG. 5B shows a simulated energy band structure and carrier concentration of a device structure under 6V of forward bias without the n-GaN interlayer between a short period superlattice (SPS) region and a singlesegment (SS) active region.

[0022] The effect of the addition of the hole blocking n-GaN interlayer between the singlesegment active region and the SPS is shown in FIGS. 5A and 5B. A simulated band diagram and carrier concentrations of the structure with a thin n-GaN spacer layer under 6 V of bias, obtained with Silvaco ATLAS is shown in FIG. 5A. A simulated band diagram and carrier concentrations of the structure with a thick n-GaN spacer layer under 6 V of bias, obtained with Silvaco ATLAS is shown in FIG. 5B. With an additional n-GaN interlayer that is 20 nm in thickness, hole concentrations in the SPS InGaN layers are suppressed by more than three orders of magnitude. The n-GaN interlayer blocks the holes from overflowing into the SPS and thus effectively suppresses the parasitic green EL from the SPS, leading to stable red emissionover a wide range of carrier injection conditions. It is important to note that such an n-GaN interlayer between the active region and the SPS underneath comes with potential tradeoffs too, since too thick of such a layer could negate the pseudomorphic strain relief brought by the SPS underneath.

[0023] Referring again to FIGS. 1A and IB, aspects of the present technology advantageously enable high efficiency, (sub)micron length scale, and robust red emission under various operating conditions for LEDs. Though relatively efficient red-emitting micro-LEDs have been reported previously, which are represented FIG. IB, they exhibited a significant blue-shift in emission to the orange or yellow wavelengths at elevated current injection levels.

[0024] Embodiments of the present technology advantageously realizes a high-efficiency, near submicron scale micro-LED device that both achieves red emission, which is commonly defined as emission with wavelengths between 620 nm and 750 nm, and stays red over two orders of magnitude variation in current injection. In embodiments, an InGaN-based micro-LED emission generating a wavelength longer than 650 nm at the maximal external quantum efficiency (EQE) operating point. At a peak EQE of 3.3%, the device shows electroluminescence at approximately 660 nm. In embodiments, embodiments of the present technology achieve red color stability with a growth strategy including an active region strain management that allows for efficient indium incorporation, such that the device remains in the red spectrum range despite the associated quantum-confined Stark effect (QCSE). Aspects of the present technology can advantageously be utilized to realize efficient micro-LED RGB systems via InGaN bottom-up nanostructures.

[0025] The following examples pertain to specific technology embodiments and point out specific features, elements, or steps that may be used or otherwise combined in achieving such embodiments.

[0026] Example 1 includes a light emitting device comprising one or more nanowires. Each nanowire can include a N-polar semiconductor region having a first doping type; an indium gallium nitride / gallium nitride (InGaN / GaN) N-polar short period superlattice (SPSL) region, having the first doping type, disposed on the N-polar semiconductor region; an indium gallium nitride (InGaN) N-polar single-segment (SS) active region disposed on the InGaN / GaN N-polar short period superlattice (SPSL) region opposite the N-polar semiconductor region; and a tunnel junction region, having a second doping type, disposed on the InGaN N-polar single-segment (SS) active region opposite the InGaN / GaN N-polar short period superlattice (SPSL) region.

[0027] Example 2 includes the light emitting device including the one or more nanowires according to Example 1, each nanowire further comprising: a gallium nitride (GaN) N-polar spacer, having the first doping type, disposed between the InGaN N-polar single-segment (SS) active region and the InGaN / GaN N-polar short period superlattice (SPSL) region.

[0028] Example 3 includes the light emitting device including the one or more nanowires according to Example 2, wherein the gallium nitride (GaN) N-polar spacer comprises a hole blocking layer.

[0029] Example 4 includes the light emitting device including the one or more nanowires according to Example 2, each nanowire further comprising: a gallium nitride (GaN) N-polar buffer, having an intrinsic doping, disposed between the InGaN N-polar single-segment (SS) active region and the GaN N-polar spacer.

[0030] Example 5 includes the light emitting device including the one or more nanowires according to Example 1, wherein the concentration of indium {In) in one or more of the InGaN N-polar single-segment (SS) active region and the InGaN / GaN N-polar short period superlattice (SPSL) region is greater than 15% in the InGaN layers.

[0031] Example 6 includes the light emitting device including the one or more nanowires according to Example 1, wherein the concentration of indium (In) in one or more of the InGaN N-polar single-segment (SS) active region and the InGaN / GaN N-polar short period superlattice (SPSL) region is approximately 30% in the InGaN layers.

[0032] Example 7 includes the light emitting device including the one or more nanowires according to Example 1, wherein the indium gallium nitride (InGaN) N-polar single-segment (SS) active region emits red light with an external quantum efficiency (EQE) of over 3%.

[0033] Example 8 includes the light emitting device including the one or more nanowires according to Example 1, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region comprises silicon (Si) doping.

[0034] Example 9 includes the light emitting device including the one or more nanowires according to Example 1, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region comprises a single segment of N-polar InGaN.

[0035] Example 10 includes the light emitting device including the one or more nanowires according to Example 1, wherein the tunnel junction region comprises a magnesium doped gallium nitride (GaN) layer.

[0036] Example 11 includes a method of fabricating a light emitting device comprising: epitaxial depositing an N-polar indium gallium nitride / gallium nitride (InGaN / GaN) short period superlattice (SPSL) nanowire region having a first doping type on a N-polar semiconductor nanowire region having the first doping type; epitaxial depositing an N-polar indium gallium nitride (InGaN) single-segment (SS) active nanowire region on the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region opposite the N-polar semiconductor nanowire region; and epitaxial depositing a tunnel junction nanowire region, having a second doping type, on the N-polar InGaN N-polar single-segment (SS) active nanowire region opposite the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region.

[0037] Example 12 includes the method of fabricating the light emitting device of Example 11, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region is doped with silicon (Si).

[0038] Example 13 includes the method of fabricating the light emitting device of Example 11, wherein the concentration of indium (In) in the InGaN N-polar single-segment (SS) active nanowire region is greater than 15% in the InGaN layer.

[0039] Example 14 includes the method of fabricating the light emitting device of Example 11, wherein the concentration of indium (In) in the InGaN / GaN N-polar short period superlattice (SPSL) nanowire region is greater than 15% in the InGaN layers.

[0040] Example 15 includes the method of fabricating the light emitting device of Example 11, further comprising: epitaxial depositing a N-polar gallium nitride (GaN) spacer nanowire region, having the first doping type, disposed between the N-polar InGaN single-segment (SS) active nanowire region and the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region.

[0041] Example 16 includes the method of fabricating the light emitting device of Example 15, wherein the N-polar gallium nitride (GaN) nanowire spacer is approximately 20 nanometers (nm) thick.

[0042] Example 17 includes the method of fabricating the light emitting device of Example 15, further comprising: epitaxial depositing a N-polar gallium nitride (GaN) buffer nanowire region, having an intrinsic doping, disposed between the N-polar InGaN single-segment (SS) active nanowire region and the N-polar GaN spacer nanowire region.

[0043] Example 18 includes the method of fabricating the light emitting device of Example 17, further comprising: forming a nanowire mask on a substrate; and epitaxial depositing the N- polar semiconductor nanowire region on the substrate in opening in the nanowire mask.

[0044] Example 19 includes the method of fabricating the light emitting device of Example 18, wherein the epitaxial depositing comprises molecular beam epitaxy (MBE).

[0045] The foregoing descriptions of specific embodiments of the present technology have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present technology and its practical application, to thereby enable others skilled in the art to best utilize the present technology and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

Claims1. A light emitting device including one or more nanowires, each nanowire comprising: a N-polar semiconductor region having a first doping type; an indium gallium nitride / gallium nitride (InGaN / GaN) N-polar short period superlattice (SPSL) region, having the first doping type, disposed on the N-polar semiconductor region; an indium gallium nitride (InGaN) N-polar single-segment (SS) active region disposed on the InGaN / GaN N-polar short period superlattice (SPSL) region opposite the N-polar semiconductor region; and a tunnel junction region, having a second doping type, disposed on the InGaN N-polar single-segment (SS) active region opposite the InGaN / GaN N-polar short period superlattice (SPSL) region.

2. The light emitting device including the one or more nanowires according to Claim 1, each nanowire further comprising: a gallium nitride (GaN) N-polar spacer, having the first doping type, disposed between the InGaN N-polar single-segment (SS) active region and the InGaN / GaN N-polar short period superlattice (SPSL) region.

3. The light emitting device including the one or more nanowires according to Claim 2, wherein the gallium nitride (GaN) N-polar spacer comprises a hole blocking layer.

4. The light emitting device including the one or more nanowires according to Claim 2, each nanowire further comprising: a gallium nitride (GaN) N-polar buffer, having an intrinsic doping, disposed between the InGaN N-polar single-segment (SS) active region and the GaN N-polar spacer.

5. The light emitting device including the one or more nanowires according to Claim 1, wherein a concentration of indium (In) in one or more of the InGaN N-polar single-segment (SS) active region and the InGaN / GaN N-polar short period superlattice (SPSL) region is greater than 15% in the InGaN layers.

6. The light emitting device including the one or more nanowires according to Claim 1, wherein a concentration of indium (In) in one or more of the InGaN N-polar single-segment (SS) activeregion and the InGaN / GaN N-polar short period superlattice (SPSL) region is approximately 30% in the InGaN layers.

7. The light emitting device including the one or more nanowires according to Claim 1, wherein the indium gallium nitride (InGaN) N-polar single-segment (SS) active region emits red light with an external quantum efficiency (EQE) of over 3%.

8. The light emitting device including the one or more nanowires according to Claim 1, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region comprises silicon (Si) doping.

9. The light emitting device including the one or more nanowires according to Claim 1, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region comprises a single segment of N- polar InGaN.

10. The light emitting device including the one or more nanowires according to Claim 1, wherein the tunnel junction region comprises a magnesium doped gallium nitride (GaN) layer.

11. A method of fabricating a light emitting device comprising: epitaxial depositing an N-polar indium gallium nitride / gallium nitride (InGaN / GaN) short period superlattice (SPSL) nanowire region having a first doping type on a N-polar semiconductor nanowire region having the first doping type; epitaxial depositing an N-polar indium gallium nitride (InGaN) single-segment (SS) active nanowire region on the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region opposite the N-polar semiconductor nanowire region; and epitaxial depositing a tunnel junction nanowire region, having a second doping type, on the N-polar InGaN N-polar single-segment (SS) active nanowire region opposite the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region.

12. The method of fabricating the light emitting device of Claim 11, wherein the InGaN / GaN N-polar short period superlattice (SPSL) region is doped with silicon (Si).

13. The method of fabricating the light emitting device of Claim 11, wherein a concentration of indium (In) in the InGaN N-polar single-segment (SS) active nanowire region is greater than 15% in the InGaN layer.

14. The method of fabricating the light emitting device of Claim 11, wherein a concentration of indium (In) in the InGaN / GaN N-polar short period superlattice (SPSL) nanowire region is greater than 15% in the InGaN layers.

15. The method of fabricating the light emitting device of Claim 11, further comprising: epitaxial depositing a N-polar gallium nitride (GaN) spacer nanowire region, having the first doping type, disposed between the N-polar InGaN single-segment (SS) active nanowire region and the N-polar InGaN / GaN short period superlattice (SPSL) nanowire region.

16. The method of fabricating the light emitting device of Claim 15, wherein the N-polar gallium nitride (GaN) nanowire spacer is approximately 20 nanometers (nm) thick.

17. The method of fabricating the light emitting device of Claim 15, further comprising: epitaxial depositing a N-polar gallium nitride (GaN) buffer nanowire region, having an intrinsic doping, disposed between the N-polar InGaN single-segment (SS) active nanowire region and the N-polar GaN spacer nanowire region.

18. The method of fabricating the light emitting device of Claim 17, further comprising: forming a nanowire mask on a substrate; and epitaxial depositing the N-polar semiconductor nanowire region on the substrate in opening in the nanowire mask.

19. The method of fabricating the light emitting device of Claim 18, wherein the epitaxial depositing comprises molecular beam epitaxy (MBE).

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