Electroluminescence efficiency of blue InGaN/GaN quantum-well diodes with and without an n-InGaN electron reservoir layer

The temperature dependence of the electroluminescence (EL) spectral intensity has been investigated in detail between T=20 and 300 K at various injection current levels for a set of two blue InGaN/GaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with and without an additional n-doped In0.18Ga0.82N electron reservoir layer (ERL). The radiative recombination efficiency of the main blue emission band (~480 nm) is found to be significantly improved at all temperature regions and current levels when the additional ERL is introduced. For high injection currents If, i.e., large forward bias voltages Vf, a quenching of the EL intensity is observed for T<100 K for both LED structures, accompanying appearance of short-wavelength satellite emissions around 380–430 nm. Furthermore, the low-temperature intensity reduction of the main EL band is stronger for the LED without the ERL than with the ERL. For low If, i.e., small Vf, however, no quenching of the EL intensity is observed for both LEDs even below 100 K and the short-wavelength satellite emissions are significantly reduced. These results of the main blue emission and the short-wavelength satellite bands imply that the unusual evolution of the EL intensity with temperature and current is caused by variations of the actual potential field distribution due to both internal and external fields. They significantly influence the carrier capture efficiency by radiative recombination centers within the active MQW layer and the carrier escape out of the active regions into high-energy recombination centers responsible for the short-wavelength satellite emissions

Electroluminescence efficiency of blue InGaN/GaN quantum-well diodes with and without an n-InGaN electron reservoir layer

The temperature dependence of the electroluminescence (EL) spectral intensity has been investigated in detail between T=20 and 300 K at various injection current levels for a set of two blue InGaN/GaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with and without an additional n-doped In0.18Ga0.82N electron reservoir layer (ERL). The radiative recombination efficiency of the main blue emission band (~480 nm) is found to be significantly improved at all temperature regions and current levels when the additional ERL is introduced. For high injection currents If, i.e., large forward bias voltages Vf, a quenching of the EL intensity is observed for T<100 K for both LED structures, accompanying appearance of short-wavelength satellite emissions around 380–430 nm. Furthermore, the low-temperature intensity reduction of the main EL band is stronger for the LED without the ERL than with the ERL. For low If, i.e., small Vf, however, no quenching of the EL intensity is observed for both LEDs even below 100 K and the short-wavelength satellite emissions are significantly reduced. These results of the main blue emission and the short-wavelength satellite bands imply that the unusual evolution of the EL intensity with temperature and current is caused by variations of the actual potential field distribution due to both internal and external fields. They significantly influence the carrier capture efficiency by radiative recombination centers within the active MQW layer and the carrier escape out of the active regions into high-energy recombination centers responsible for the short-wavelength satellite emissions

Zircons in metacarbonate rocks from Sør Rondane Mountains, East Antarctica

第6回極域科学シンポジウム[OG] 地圏11月16日（月）　国立極地研究所３階セミナー

Apparent age of deposition of meta-carbonate rocks from Sør Rondane Mountains, East Antarctica

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日（木） 国立極地研究所　2階大会議

Comparison of chemically estimated depositional ages with zircon SHRIMP ages from metacarbonate rocks in the Sør Rondane Mountains, East Antarctica

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 国立極地研究所 ３階ラウン

Room Temperature Coherent and Voltage Tunable Terahertz Emission from Nanometer-Sized Field Effect Transistors

We report on reflective electro-optic sampling measurements of TeraHertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. We establish that the physical mechanism of the coherent TeraHertz emission is related to the plasma waves driven by simultaneous current and optical excitation. A significant shift of the plasma frequency and the narrowing of the emission with increasing channel's current are observed and explained as due to the increase of the carriers density and drift velocity.Comment: 3 figure