Red InGaN nanowire LED with bulk active region directly grown on p-Si (111)

Abstract

A red nanowire LED with an InGaN bulk active region, directly grown on a p-Si (111) substrate, is demonstrated. The LED exhibits relatively good wavelength stability upon increasing injection current and narrowing of the linewidth without quantum confined Stark effect. Efficiency droop sets in at relatively high injection current. The output power and external quantum efficiency are 0.55 mW and 1.4% at 20 mA (20 A/cm2) with peak wavelength of 640 nm, reaching 2.3% at 70 mA with peak wavelength of 625 nm. The operation on the p-Si substrate results in large carrier injection currents due to a naturally formed tunnel junction at the n-GaN/p-Si interface and is ideal for device integration.

In Desorption in InGaN Nanowire Growth on Si Generates a Unique Light Emitter: From In-Rich InGaN to the Intermediate Core–Shell InGaN to Pure GaN

“…The core–shell InGaN NW2 structure, grown at the temperature slightly above the onset of In desorption, is elucidated as the active region of our red InGaN nanowire LED with the bulk active region directly grown on p-Si(111) . Its ideal structural properties, next to the wavelength stability due to the absence of the quantum confined Stark effect, reduced efficiency droop and carrier heating due to low carrier densities, absence of carrier overflow due to efficient carrier capture, and enhanced light extraction due to light scattering are highlighted by three main points: First, the elevated growth temperature, slightly above the onset of In desorption maximizes the crystal quality of the active region, while the self-formed, In-rich InGaN NW core maintains emission in the red.…”

Planar GaN/Cu2O Microcrystal Composite Junction Photoanode for Efficient Solar Water Splitting

“…Electrodes were fabricated using ∼0.5 cm 2 samples, brought in contact at the back side with GaIn eutectic, and glued on a Cu tape supported on a glass plate. This takes advantage of the ohmic contact between n-GaN and p-Si where the GaN layer is unintentionally n-type due to defects acting as donors . Silicon rubber was used for insulation, leaving a ∼ 0.03 cm 2 window for contact with the electrolyte.…”

“…This takes advantage of the ohmic contact between n-GaN and p-Si where the GaN layer is unintentionally n-type due to defects acting as donors. 34 Silicon rubber was used for insulation, leaving a ∼ 0.03 cm 2 window for contact with the electrolyte. The GaN working electrode, a saturated calomel electrode (SCE) reference electrode, and a Pt mesh counter electrode were connected to an electrochemical workstation.…”

Transition from Metal-Rich to N-Rich Growth for Core–Shell InGaN Nanowires on Si (111) at the Onset of In Desorption

“…InGaN is the ideal semiconductor material for light-emitting devices in the huge lighting and display sectors owing to the composition-dependent direct energy band gap spanning the spectral range from the infrared for InN (0.7 eV) to the ultraviolet for GaN (3.4 eV). − Furthermore, the direct growth of In-rich InGaN on Si allows the design of new optoelectronic devices operating in the red to near-infrared spectral regions and their direct integration with Si microelectronics. − In particular, the substrate induced nanowire (NW) formation, allowing low N fluxes close to the metal-rich to N-rich growth transition for highest structural and optical quality, and the natural formation of core–shell InGaN NWs with an In-rich core and an In-poor shell, slightly above the onset of In desorption offers unique device opportunities . Such core–shell InGaN NWs have been identified by transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) analysis and employed as the active region of red light-emitting diodes in our previous work. , The core–shell InGaN NWs form at and above the onset of In desorption due to preferential In desorption during In diffusion up the NWs on the m-plane NW sidewalls, contributing to the formation of the In-poor shell, while In desorption during In diffusion to the NW center on the c-plane NW tops, contributing to the formation of the In-rich core, is largely negligible. ,− The increase of In desorption for the InGaN NW shell formation is gradual and depends on the growth temperature, N flux, and metal fluxes.…”

“…8 Such core−shell InGaN NWs have been identified by transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) analysis and employed as the active region of red light-emitting diodes in our previous work. 8,9 The core−shell InGaN NWs form at and above the onset of In desorption due to preferential In desorption during In diffusion up the NWs on the m-plane NW sidewalls, contributing to the formation of the In-poor shell, while In desorption during In diffusion to the NW center on the c-plane NW tops, contributing to the formation of the In-rich core, is largely negligible. 6,10−15 The increase of In desorption for the InGaN NW shell formation is gradual and depends on the growth temperature, N flux, and metal fluxes.…”