Broadband White-Light Emission from Alumina Nitride Bulk Single Crystals

Abstract

Alumina nitride bulk single crystals (AlN BSCs) were grown using a two-heater Physical Vapor Transport (th-PVT) method. The crystal contains massive lattice defects including aluminum vacancy (VAl) and oxygen substitution (ON). The photoluminescence (PL) spectrum of the crystal demonstrated a broad emission covering from 250 to 1000 nm. By study the PL spectrum, abundant midgap states in the wide band gap of AlN were nailed down. Based on the crystals, metal-AlN-metal Schottky devices were fabricated. These devices emitted high quality white light with color rendering index (CRI) over 90 under a bias of 60 V. Moreover, it was found that the white light emitting property of AlN BSCs was adjustable through changing impurity density and device structure. This research aims to pave a new way for solid-state white light source.

Single-Photon Emission from Point Defects in Aluminum Nitride Films

“…18 Additionally, Liu et al introduced the broadband white-light emission from lattice defects from AlN bulk single crystals. 21 Although defect-related emissions in AlN have been reported, SPEs of single defects have not been studied in detail. Note that there was a short conference report on the high-purity SPEs in 200 nm AlN film, corresponding to the emission wavelength of approximately 596 nm.…”

“…For these SPEs, point defects in wide-bandgap semiconductors are one of the more promising quantum emitters that have been studied recently, due to their unique properties and potential applications. − To date, defect-related SPEs have been reported in wide-bandgap semiconductors, such as in diamond, zinc oxide, silicon carbide (SiC), hexagonal boron nitride (hBN), and gallium nitride. − Aluminum nitride (AlN) is also a wide-bandgap semiconductor with an optical transition energy of approximately 6.1 eV. AlN is a key semiconductor for next-generation photonic and electronic devices, especially in high-power electronics and high-temperature applications. , Recently, defect-related absorption and photoluminescence (PL) have been reported in AlN. − For example, Lamprecht et al discussed a model for the deep defect-related emission bands between 1.4 and 2.4 eV . Schulz et al investigated defect-related PL in the near UV region between 3 and 4 eV .…”

“…Schulz et al investigated defect-related PL in the near UV region between 3 and 4 eV . Additionally, Liu et al introduced the broadband white-light emission from lattice defects from AlN bulk single crystals …”

Supercontinuum Generation in High Order Waveguide Mode with near-Visible Pumping Using Aluminum Nitride Waveguides

“…Notably, irreversible material damage was occurred, inducing material defects that can be readily identified under the microscope via white light luminescence from defect states. 34 To avoid this irreversible damage, the onchip power was kept at least two times lower than this value.…”

“…It should be noted that when the on-chip average power exceeds ∼100 mW, behaviors indicative of thermal melting or dielectric breakdown began to be observed (Figure S3). Notably, irreversible material damage was occurred, inducing material defects that can be readily identified under the microscope via white light luminescence from defect states . To avoid this irreversible damage, the on-chip power was kept at least two times lower than this value.…”