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GaN/AlxGa1-xN quantum wells were grown by molecular beam epitaxy on high quality bulk (0001) GaN substrates. The quantum well thickness was set in the 6-8 nm range to favor the photoluminescence emission of indirect excitons. Indeed, such…

Tunnel-injection lasers promise advantages in modulation bandwidth and temperature stability in comparison to conventional laser designs. In this paper, we present results of a microscopic theory for laser properties of tunnel-injection…

Mesoscale and Nanoscale Physics · Physics 2018-10-17 Michael Lorke , Stephan Michael , Marian Cepok , Frank Jahnke

In the field of spin-controlled semiconductor lasers, massive effort has been focused upon materials with long spin relaxation times (~ns). In contrast, we demonstrate room-temperature spin-polarized ultrafast pulsed lasing in InGaAs…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Feng-kuo Hsu , Yi-Shan Lee , Sheng-Di Lin , Chih-Wei Lai

The influence of the growth conditions as well as the device design on the device performance of (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers is investigated. To this purpose, the epitaxy process is scaled to full two inch substrates…

InGaN-based active layers within microcavity resonators offer the potential of low threshold lasers in the blue spectral range. Here we demonstrate optically pumped, room temperature lasing in high quality factor GaN microdisk cavities…

High power single mode quantum cascade lasers with a narrow far field are important for several applications including surgery or military countermeasure. Existing technologies suffer from drawbacks such as operation temperature and…

We investigate the radiative and nonradiative recombination processes in planar (In,Ga)N/GaN(0001) quantum wells and (In,Ga)N quantum disks embedded in GaN$(000\bar{1})$ nanowires using photoluminescence spectroscopy under both…

Mesoscale and Nanoscale Physics · Physics 2017-07-31 F. Feix , T. Flissikowski , K. K. Sabelfeld , V. M. Kaganer , M. Wölz , L. Geelhaar , H. T. Grahn , O. Brandt

We study the electronic properties of spherical quantum dot quantum well nanocrystals within a symmetry-based tight-binding model. In particular, the influence of a concentric monolayer of HgS embedded in a spherical CdS nanocrystal of…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 J. Perez-Conde , A. K. Bhattacharjee

Drift-diffusion computer simulations model available in Synopsys' Sentaurus TCAD is used to study electrical, I-V, and optical, I-L, characteristics of separate-confinement heterostructure laser based on $AlGaAs$. We investigate the role of…

Materials Science · Physics 2013-02-05 Zbigniew Koziol , Sergey I. Matyukhin , Evgeniya A. Buduleva

Nanophotonic objects like plasmonic nanoparticles and colloidal quantum dots can complement the functionality of molecular dyes in biomedical optics. However, their operation is usually governed by spontaneous processes, which results in…

We show over 100-fold enhancement of the exciton oscillator strength as the diameter of an InGaN nanodisk in a GaN nanopillar is reduced from a few micrometers to less than 40 nm, corresponding to the quantum dot limit. The enhancement…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Lei Zhang , Leung-Kway Lee , Chu-Hsiang Teng , Tyler A. Hill , Pei-Cheng Ku , Hui Deng

Blue light-emitting diodes (LEDs) consisting of a buried n+-p+ GaN tunnel junction, (In,Ga)N multiple quantum wells (MQWs) and a n+-GaN top layer are grown on single-crystal Ga-polar n+-GaN bulk wafers by plasma-assisted molecular beam…

Applied Physics · Physics 2019-06-26 YongJin Cho , Shyam Bharadwaj , Zongyang Hu , Kazuki Nomoto , Uwe Jahn , Huili Grace Xing , Debdeep Jena

The photoluminescence of III-V wide band-gap semiconductors as InGaN is characterized by local intensity fluctuations, known as 'blinking points', that despite decades of research are not yet completely understood. In this letter we report…

Optics · Physics 2015-06-04 R. Micheletto , K. Oikawa , C. Feldmeier

We present a self-consistent approach to describe ambipolar tunneling in asymmetrical double quantum wells under steady-state excitation and extend the results to the case of tunneling from a near-surface quantum well to surface states. The…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Carlo Presilla , Valentina Emiliani , Andrea Frova

We present a theoretical analysis and optimisation of the properties and performance of mid-infrared semiconductor lasers based on the dilute bismide alloy In$_{x}$Ga$_{1-x}$As$_{1-y}$Bi$_{y}$, grown on conventional (001) InP substrates.…

The electron density of states in the open quantum well formed by the downward band bending region at the surface of cesiated p-type GaN is investigated. We theoretically predict the existence of metastable resonant states in this non…

Even distribution of carriers allows to maximize optical gain of the Optically-Pumped Vertical External Cavity Surface Emitting Laser. In this paper we show how to distribute the quantum wells and blocking layers in order to compensate the…

Optics · Physics 2012-04-09 M. Wasiak

Solid state lasers are demanding independent control in the gain media and cavity loss to achieve ultra short laser pulses using passive mode-locking. Recently, laser mode-locking is achieved with a MBE structure with multiple quantum…

We present a theoretical investigation of space separated electron and hole distributions, which consists in the self-consistent solving of the Schrodinger equations for electrons and holes and the Poisson equation. The results are…

Mesoscale and Nanoscale Physics · Physics 2013-02-13 L. O. Lokot

It should be possible to improve hot-hole laser performance by moving from bulk materials to a quantum well structure. The extra design parameters enable us to alter the band structure by changing the crystal orientation of the growth…

Condensed Matter · Physics 2014-08-04 P. Kinsler , W. Th. Wenckebach