Blue II-VI laser Diodes and light Emitting Diodes

1992 ◽  
Vol 281 ◽  
Author(s):  
R. L. Gunshor ◽  
A. V. Nurmikko ◽  
N. Otsuka
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Plasma Source ◽  
Threshold Current ◽  
Rf Plasma ◽  
Plan View ◽  
Light Emitting ◽  
Dislocation Densities ◽  
Power Outputs ◽  
P Type

ABSTRACTThe use of a nitrogen rf plasma source for p-type ZnSe grown by MBE, has allowed a variety of pn junction based devices to be realized. The pn junctions have been combined with (Zn,Cd)Se quantum wells to implement semiconductor injection lasers, operating in the blue/green portion of the spectrum, which were reported by 3M and the Brown/Purdue group in the summer of 1991. In the past year the field has moved rapidly. In particular, we can now report CW operation at low temperatures as well as pulsed operation at room temperature (490nm) using a Zn(S,Se)-based device configuration. Laser power output per facet for some designs is above 300 mW, and threshold current densities are as low as 1000A/cm 2 at room temperature. Lasing was demonstrated from devices grown on both p and n-type GaAs substrates. X-ray rocking curves of theII-VI regions exhibit FWHM values below 20 arcsec for specific samples. Dislocation densities are less than 105 cm−2, below the threshold of TEM plan view imaging. The blue LEDs provide power outputs in excess of 100μW while exhibiting external quantum efficiencies of 0.1% at room temperature.

Comparison between the Photoluminescence Mappings Under Selective and Non-selective Excitation and the Electroluminescence Mappings of the Epitaxial Wafers with InGaN-LED Structure

2006 ◽  
Vol 955 ◽  
Author(s):  
Kazuyuki Tadatomo ◽  
Osamu Shimoike ◽  
Hiromichi Noda ◽  
Masahiro Hiraoka ◽  
Kazumasa Yoshimura ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Selective Excitation ◽  
Excitation Power ◽  
Excitation Power Density ◽  
Peak Wavelength ◽  
Light Emitting ◽  
Forward Current ◽  
Pl Mapping ◽  
P Type

ABSTRACTWe compared the photoluminescence (PL) mappings of epitaxial wafers for light emitting diodes (LEDs) by using a He-Cd laser (325 nm line) and a laser diode (LD) with peak wavelength of 405 nm as excitation sources and the electroluminescence (EL) mappings of the same wafers. The samples were epitaxial wafers for blue and green InGaN-LEDs obtained in commercial. The wafers were fabricated into LEDs with a Ni/Au transparent p-type electrode and a Ti/Ni n-type electrode after the PL mapping measurements. The He-Cd laser performed the band to band excitation of (Al)GaN cladding and contact layers (non-selective excitation). Because the photo-excited carriers at the cladding and contact layers diffused into the multi-quantum wells (MQWs) and contributed the PL emission by radiative recombination in the MQWs, the PL mapping under the influence of the (Al)GaN cladding and contact layers was obtained. On the other hand, the LD (405 nm) enable us to obtain the PL mapping under selective excitation of the MQWs without the influence of the cladding and contact layers. The PL mapping measurements were carried out at room temperature (RT) at the excitation power density of 310 W/cm2 under non-selective excitation (by the He-Cd laser) and at that of 11.5 W/cm2 under selective excitation (by the LD). The EL mapping was measured at a forward current of 20 mA at RT. The area of the wafer with high EL intensity was coincident with the area with the high PL intensity under selective excitation. Therefore, the PL mapping measurement under selective excitation of MQWs is recommended to characterize the epitaxial wafers and to estimate the device performance of InGaN-LEDs.

1.5 micron InAs quantum dot lasers based on metamorphic InGaAs/GaAs heterostructures.

2003 ◽  
Vol 794 ◽  
Author(s):  
V.M. Ustinov ◽  
A.E. Zhukov ◽  
A.R. Kovsh ◽  
N.A. Maleev ◽  
S.S. Mikhrin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Active Region ◽  
Quantum Wells ◽  
Gaas Substrate ◽  
Room Temperature ◽  
Internal Quantum Efficiency ◽  
Characteristic Temperature ◽  
Optical Loss ◽  
Threshold Current ◽  
Temperature Threshold

ABSTRACT1.5 micron range emission has been realized using the InAs quantum dots embedded into the metamorphic InGaAs layer containing 20% of InAs grown by MBE on a GaAs substrate. Growth regimes were optimized to reduce significantly the density of dislocations propagating into the active layer from the lattice mismatched interface. 2 mm long InGaAs/InGaAlAs lasers with 10 planes of quantum dots in the active region showed threshold current density about 1.4 kA/cm2 with the external differential efficiency as high as 38%. Lasing wavelength depends on the optical loss being in the 1.44–1.49 micron range at room temperature. On increasing the temperature the wavelength reaches 1.515 micron at 85C while the threshold current characteristic temperature of 55–60K was estimated. High internal quantum efficiency (η>60%)and low internal losses (α=3–4 cm ) were realized. Maximum room temperature output power in pulsed regime as high as 5.5 W for 100 micron wide stripe was demonstrated. Using the same concept 1.3 micron InGaAs/InGaAlAs quantum well lasers were fabricated. The active region contained quantum wells with high (∼40%) indium content which was possible due to the intermediate InGaAs strain relaxation layer. 1 mm stripe lasers showed room temperature threshold current densities about 3.3 kA/cm (λ=1.29 micron) and 400 A/cm2 at 85K. Thus, the use of metamorphic InGaAs layers on GaAs substrate is a very promising approach for increasing the emission wavelength of GaAs based lasers.

Room temperature electroluminescence from arsenic doped p-type ZnO nanowires/n-ZnO thin film homojunction light-emitting diode

2014 ◽  
Vol 25 (4) ◽  
pp. 1955-1958 ◽  
Author(s):  
Hongwei Liang ◽  
Qiuju Feng ◽  
Xiaochuan Xia ◽  
Rong Li ◽  
Huiying Guo ◽  
...  
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Light Emitting Diode ◽  
Zno Nanowires ◽  
Zno Thin Film ◽  
Light Emitting ◽  
P Type

High Luminescence Efficiency from GaAsN Layers Grown by MBE with RF Nitrogen Plasma Source

2001 ◽  
Vol 692 ◽  
Author(s):  
Victor M. Ustinov ◽  
Nikolai A. Cherkashin ◽  
Nikolai A. Bert ◽  
Andrei F. Tsatsul'nikov ◽  
Alexei R. Kovsh ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Plasma Source ◽  
Peak Position ◽  
Nitrogen Plasma ◽  
Rf Plasma ◽  
Photoluminescence Intensity ◽  
Temperature Growth ◽  
Luminescence Efficiency ◽  
Lower Temperature ◽  
Reference Layer

Abstract(In)GaAsN based heterostructures have been found to be promising candidates for the active region of 1.3 micron VCSELs. However, (In)GaAsN bulk layers and quantum wells usually demonstrate lower photoluminescence intensity than their nitrogen-free analogues. Defects associated with lower temperature growth and N-related defects due to plasma cell operation and possible nonuniform distribution of nitrogen enhance the non-radiative recombination in N-contained layers. We studied the photoluminescence intensity of GaAsN layers as a function of N content in MBE grown samples using rf-plasma source. Increasing the growth temperature to as high as 520 °C in combination with the increase in the growth rate allowed us to avoid any N-related defects up to 1.5% of nitrogen. Low-temperature-growth defects can be removed by post-growth annealing. We achieved the same radiative efficiency of GaAsN samples grown at 520°C with that of reference layer of GaAs grown at 600°C. Compositional fluctuations in GaAsN layers lead to characteristic S-shape of temperature dependence of photoluminescence peak position and this feature is the more pronounced the higher the amount of nitrogen in GaAsN. Annealing reduces compositional fluctuations in addition to the increase in the photoluminescence intensity. The results obtained are important for further improving the characteristics of InGaAsN lasers emitting at 1.3 micron.

Interband Semiconductor Lasers and LEDs

2020 ◽  
pp. 421-490
Author(s):  
Vurgaftman Igor
Keyword(s):  
Quantum Wells ◽  
Semiconductor Lasers ◽  
High Speed ◽  
Diode Lasers ◽  
Spectral Characteristics ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Light Emitting ◽  
Speed Modulation ◽  
Interband Cascade Lasers

This chapter discusses the operation of conventional diode lasers based on quantum wells and quantum dots as a function of emission wavelength. The recombination processes that control the threshold current density of the devices are described in detail, including recombination at defects, radiative, and Auger recombination. The high-speed modulation and spectral characteristics of semiconductor lasers are also discussed. It continues by illustrating why interband cascade lasers can outperform diode lasers at mid-infrared wavelengths and describing their design and operating characteristics in detail. On the short-wavelength side of the spectrum, the nitride lasers and the factors that limit their performance are discussed. In addition to lasers, the principles underlying light-emitting diodes (LEDs) are outlined, and the proposed mechanisms for improving the extraction of the light from high-index semiconductor materials are described. The chapter concludes with a discussion of the performance of semiconductor optical amplifiers designed to amplify a weak input signal.

Investigation of GaN-based dual-wavelength light-emitting diodes with p-type barriers and vertically stacked quantum wells

2012 ◽  
Vol 10 (6) ◽  
pp. 062302-62306
Author(s):  
Jun Chen Jun Chen ◽  
Guanghan Fan Guanghan Fan ◽  
Wei Pang Wei Pang ◽  
Shuwen Zheng Shuwen Zheng ◽  
Yunyan Zhang Yunyan Zhang
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diodes ◽  
Dual Wavelength ◽  
Light Emitting ◽  
P Type ◽  
Wavelength Light

Origins and suppressions of parasitic emissions in ultraviolet light-emitting diode structures

2010 ◽  
Vol 25 (6) ◽  
pp. 1037-1040 ◽  
Author(s):  
Weihuang Yang ◽  
Shuping Li ◽  
Hangyang Chen ◽  
Dayi Liu ◽  
Junyong Kang
Keyword(s):  
Quantum Wells ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Force Microscopy ◽  
Uv Led ◽  
Hole Blocking Layer ◽  
To Come ◽  
P Type

The AlGaN-based ultraviolet (UV) light-emitting diode (LED) structures with AlN as buffer were grown on sapphire substrate by metalorganic vapor-phase epitaxy (MOVPE). A series of cathodoluminescence (CL) spectra were measured from the cross section of the UV-LED structure using point-by-point sampling to investigate the origins of the broad parasitic emissions between 300 and 400 nm, and they were found to come from the n-type AlGaN and AlN layers rather than p-type AlGaN. The parasitic emissions were effectively suppressed by adding an n-type AlN as the hole-blocking layer. Electroluminescence (EL) and atomic force microscopy (AFM) measurements have revealed that the interface abruptness and crystalline quality of the UV-LED structure are essential for the achievement of the EL emissions from the multiple quantum wells (MQWs).

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