V-shaped dislocations in a GaN epitaxial layer on GaN substrate

In this study, V-shaped dislocations in a GaN epitaxial layer on a free-standing GaN substrate were observed. Our investigation further revealed that the V-shaped dislocations were newly generated at the interface in the epilayer rather than propagated from the GaN substrate. V-shaped dislocations consist of two straight parts. The straight parts of the V-shaped dislocations were separated from each other in the m-direction and tilted toward the step-flow direction of the GaN epitaxial layer. The V-shaped dislocations are continuous single dislocations having a Burgers vector component of 1a and an intrinsic stacking fault between their straight parts

Photoluminescence Properties of Implanted Praseodymium into Gallium Nitride at Elevated Temperature

In this study, we investigate the photoluminescence (PL) properties of implanted Praseodymium (Pr) ions into GaN at temperatures up to 1200 oC to clarify the effect of implantation temperature on the Pr3+ activation.23rd International Workshop on Inelastic Ion-Surface Collision

Effect of photoelectrochemical etching and post-metallization annealing on gate controllability of AlGaN/GaN high electron mobility transistors

Recessed-gate AlGaN/GaN metal-insulator-semiconductor (MIS) high electron mobility transistors (HEMTs) were fabricated by utilizing a photoelectrochemical (PEC) etching and a post-metallization annealing (PMA) process. In order to demonstrate the device performance and reliability, both electrical and optical electroluminescence (EL) properties were evaluated. The capacitance-voltage (C-V) characteristic showed that the PEC etching and subsequent PMA process enhanced the gate control of two-dimensional electron gas density. The PEC-etched-gate AlGaN/GaN MIS-HEMT showed the smallest sub-threshold slope of all the samples including planar-gate and inductively coupled plasma-etchedgate devices. Furthermore, the PEC-etched devices showed an extremely low 10(-11) A mm(-1) gate leakage current with no spot-like EL. These results indicated that the PEC etching and subsequent PMA process improved the electrical properties of the Al2O3/AlGaN interface, resulting in enhanced device performance of the AlGaN/GaN MIS-HEMTs. (C) 2019 The Japan Society of Applied Physic

Optimization of Praseodymium-Implanted GaN for Single-Photon Emission

希土類ドープ窒化ガリウム半導体は狭い線幅と高い発光効率から、室温で動作する単一光子源や固体量子ビットへの応用が期待されている。しかし、その実現のためには、まず、単一希土類の観測に必要となる要素を検討し、GaN基板の選定、イオン注入条件やその後の熱処理条件の最適化が必要であることから、今回は、それら最適条件について報告する。29thICDS参加・発表のた

Luminescence Properties of Implanted Nd Ions into Submicron Regions of GaN Semiconductor

Lanthanoid-doped gallium nitride (GaN) semiconductors have attracted attention because of their high intensity luminescence and sharp room-temperature (RT) optical linewidth. GaN surfaces can be chemically functionalized and nanometer-sized particles are available, opening the door to lifescience applications such as bioimaging and biosensing. Neodymium (Nd)-doped GaN is of strong interest due to its strong near infrared luminescence at 0.9~1.1 µm which is suitable for optical imaging in biological tissues. To realize bioimaging/sensing using Nd-doped GaN nanoparticles, the small ensemble of Nd ions has to be optically detected at RT with high contrast. This paper reports photoluminescence of Nd ions implanted into submicron regions of GaN epilayer and their luminescence properties at RT. The Nd implanted square regions with the side of 250 nm were optically detected. The minimum size which was successfully fabricated and optically detected was 150 nm in this study, which supports further investigations into fluorescent nanoparticles for bioimaging applications. In the presentation, PL spectra, PL excitation spectra, saturation behavior, and luminescent transition lifetime at RT will be discusse29th Annual Meeting of MRS-

Photon emission enhancement of praseodymium ions implanted with GaN nanopillars

Lanthanoid (Ln)-doped Gallium Nitride (GaN) have attracted attentions because of their high intensity luminescence and sharp room-temperature (RT) optical linewidth. These superior luminescent properties are quite attractive for the application of single photon source (SPS) which is a key technology for quantum computing, quantum sensing, and quantum key distribution. However, one of the challenges to realize Ln-doped GaN SPS is the long luminescent transition lifetime, resulting in the low photon counts insufficient to optically detect isolated single Ln ions. Confinement of luminescent centers into nanometersized regions is an effective method to enhance their photon emission and we here we show that confinement into GaN nanopillars enhances photon emission from implanted praseodymium (Pr) ions at RT.The 8th International Conference on Nanoscience and Nanotechnology (ICONN2020