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Diode Structure (diode + structure)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Application of microsize light-emitting diode structure for monolithic optoelectronic integrated circuits

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2007
S. Y. Moon
Abstract A Si/III,V,N alloys/Si structure was grown on a Si substrate by solid-source molecular beam epitaxy (SSMBE) with an rf plasma nitrogen source and electron-beam (EB) evaporator. A two-dimensional (2D) growth mode was maintained during the growth of all layers. High-resolution X-ray diffraction (HRXRD) revealed that the structure had a small lattice mismatch to the Si substrate. InGaPN/GaPN double-heterostructure (DH) light-emitting diodes (LEDs) were fabricated on Si/III,V,N alloys/Si structure. The various sized LEDs were fabricated to put into the MOSFET for monolithic optoelectronic integrated circuits (OEIC). The luminescence properties of LEDs were evaluated by electroluminescence (EL). A double emission peak from all LED samples was observed at about 642 nm and 695 nm at room temperature (RT). As injection current increased, the emission peak wavelength changed from the peak wavelength of the InGaPN layer to that of the GaPN layer, likely due to carrier overflow of the active layer. A simplified fabrication process for the microsize LED of the unit circuit was proposed. The LEDs with emission areas from 5 × 5 ,m2 to 20 × 20 ,m2 were fabricated. The LED with an emission area of 5 × 5 ,m2 can be applied to an optical device of a monolithic OEIC. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Formation of nitride laser cavities with cleaved facets on transferred laser diodes on GaAs substrates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
Wen-Chien Yu
Abstract Smoothly cleaved facets with high reflectivities have been demonstrated on GaN laser diodes after the devices were transferred onto GaAs substrates. The GaN based laser diode structure was first fabricated by metal organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates. The samples were then mounted onto thin GaAs substrates using wafer-bonding technology. Laser lift-off (LLO) technique was applied to remove the original sapphire substrate and transfer the GaN laser structure onto GaAs substrates. Since the cubic substrates have well-defined laser cavity cleavage facet, the GaN structures bonded onto the substrates also formed smooth facets after cleavage. The cleaved facets of GaN laser diodes have been characterized using atomic force microscopy (AFM) with less than 2 nm roughness. The present study demonstrated the feasibility of transferring GaN laser structures onto other more appealing substrates for formation of laser cavities. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Observation of the second-nearest-neighbor Bloch oscillation in a GaAs/AlAs superlattice

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008
T. Hasegawa
Abstract We have systematically investigated the quantum beat of the miniband excitons and the Bloch oscillation in the Wannier-Stark (WS) localization as a function of applied bias voltage in a GaAs (6.8 nm)/AlAs (0.9 nm) superlattice embedded in a p - i - n diode structure. The coherent dynamics behaviors were detected with a reflection-type pump-probe technique. We clearly observed the transformation process from the miniband-exciton quantum beat to the Bloch oscillation with an increase in applied bias voltage producing an internal electric field. The noteworthy finding is the fact that the Bloch oscillation with the frequency of vBO = 2eFD /h appears in a weak localization regime in addition to the usual Bloch oscillation with vBO = eFD /h in a strong localization regime, where F is the electric field, and D is the superlattice period. The frequency of 2eFD /h indicates that the newly observed Bloch oscillation is due to the wave-packet motion in the second-nearest-neighbor space range. The results described above are explained by the electric-field-strength dependence of the envelope-function localization, which is estimated from the envelope-function profile calculated by a transfer-matrix method and the excitonic transitions observed by electroreflectance spectroscopy. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Profiling of light emission of GaN-based laser diodes with cathodoluminescence

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2006
M. Godlewski
Abstract Cathodoluminescence is applied for evaluation of in-plane variations of light emission from GaN-based laser diode structures. We demonstrate that potential fluctuations affect significantly emission of laser diodes for e-beam currents above thresholds for a stimulated emission. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Micro-analysis of light emission properties of GaN-based laser diodes

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
M. Godlewski
Abstract In-depth and in-plane changes of emission intensity from GaN-based laser diode structures were studied using cathodoluminescence, photoluminescence (PL), micro-PL and a Kelvin probe (potential fluctuations). We show that even at high excitation density potential fluctuations are not screened in active layers of laser diode structures. Potential fluctuations are enhanced in p-type doped layers. We also found that dislocations are formed there, which can penetrate to active region of LD devices. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]