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abstract: This paper reviews current technological developments in polarization engineering and the control of the quantum confined Stark effect (QCSE) for InxGa1 xN based quantum well active regions, which are generally employed in visible LEDs for solid state lighting applications. First, the origin of the QCSE in III N wurtzite semiconductors is introduced, and polarization induced internal fields are discussed in order to provide contextual background. Next, the optical and electrical properties of InxGa1 xN based quantum wells that are affected by the QCSE are described. Finally, several methods for controlling the QCSE of InxGa1 xN based quantum wells are discussed in the context of performance metrics of visible light emitters, considering both pros and cons. These strategies include doping control, strain/polarization field/electronic band structure control, growth direction control, and crystalline structure control.
author_names: Jae-Hyun Ryou

P Douglas Yoder

Jianping Liu

Zachary Lochner

Hyunsoo Kim

Suk Choi

Hee Jin Kim

Russell D Dupuis
title: Control of Quantum Confined Stark Effect in InGaN Based Quantum Wells
venue: IEEE Journal of Selected Topics in Quantum Electronics
year: 2009

abstract: Electro optical effects, such as the Franz Keldysh effect in bulk materials or the quantum confined Stark effect in quantum well structures, lead to strong optoelectronic nonlinearities which form the basis for optical modulators and optically bistable devices. They result from a modification of the optical absorption properties by an applied electric field and are particularly pronounced in the case of low dimensional semiconductors. We review theoretical modelling and computer simulations of such optoelectronic devices in particular for ZnSe based quantum well structures, where excitonic features dominate even at room temperature. The field dependent absorption spectra are calculated by a many body theory including the full electron electron interaction. The transition from the quantum confined Stark effect, which is found for well widths smaller than the exciton Bohr diameter, to the Franz Keldysh effect, which corresponds to the limit of wide wells, is studied. Optical bistability and switching is found in R SEED and D SEED configurations, and the optimization of the device performance is discussed. 85.60.Bt, 42.65.Pc, 78.66.Hf
author_names: Eckehard Scholl
title: Modelling of devices for optoelectronic applications: The quantum confined Stark effect and self electrooptic effect devices
year: 1999

abstract: The present work is motivated by the tremendous interest in the semiconductor nanostructures. The study of the quantum confined Stark effect (QCSE) in semiconductor superlattices and semiconductor quantum wells has attracted a lot of attention, as it is important both for fundamental physics and in devices for optoelectronic applications. The present paper is a brief review of the main electronic properties, which are the basis for the QCSE device applications of semiconductor superlattices and semiconductor quantum wells.
author_names: Stark Effect
title: ON THE MAIN APPLICATION PROPERTIES OF THE QUANTUM CONFINED
year: 2017

abstract: G. D. Sanders et al. J. Vac. Sci. Technol. B, vol. 5, No. 4, Jul/Aug. 1987, "Theory of Electroabsorption pp. 1295 1299. T. Hiroshima et al. J. Appl. Phys, vol. 62, No. 8, Oct. 1987, "Quantum Confined Stark pp. 3360 3365. Y. J. Chen et al. Phys. Review B. vol. 36, No. 8, Sep. 15, 1987, "Effect of Electric Fields." pp. 4562 4565. K. Nishi et al. Appi. Phys. Lett. vol. 51, No. 5, Aug. 3, 1987, "Enhancement of Quantum Confined pp. 320 322. M. N. Islam et al. Appl. Phys. Lett. vol. 50, No. 16,
author_names: Keith W Goossen

Matawan David

A Miller
title: United States Patent 19 Goossen et al 54 SELF ELECTROOPTIC EFFECT DEVICE EMPLOYING ASYMMETRIC QUANTUM
year: 2017

abstract: Germanium/Silicon Germanium (Ge/SiGe) multiple quantum wells receive great attention for the realization of Si based optical modulators, photodetectors, and light emitters for short distance optical interconnects on Si chips. Ge quantum wells incorporated between SiGe barriers, allowing a strong electro absorption mechanism of the quantum confined Stark effect (QCSE) within telecommunication wavelengths. In this review, we respectively discuss the current state of knowledge and progress of developing optical modulators, photodetectors, and emitters based on Ge/SiGe quantum wells. Key performance parameters, including extinction ratio, optical loss, swing bias voltages, and electric fields, and modulation bandwidth for optical modulators, dark currents, and optical responsivities for photodetectors, and emission characteristics of the structures will be presented.
author_names: Papichaya Chaisakul

V Vakarin

Jacopo Frigerio

Daniel Chrastina

Giovanni Isella

Laurent Vivien

Delphine Marris-Morini
title: Recent Progress on Ge/SiGe Quantum Well Optical Modulators, Detectors, and Emitters for Optical Interconnects
venue: Photonics
year: 2019

abstract: Electroabsorptio Abstract Electroabsorption near the optical absorption edge of quantum well materials is interesting both for physics and applications. We briefly summarize the physical mechanisms involved (e.g. the quantum confined Stark effect) and the applications to optical modulators and switching devices. Quantum wells have recently become increasingly interesting for their optical properties, especially those associated with the remarkable excitonic absorption resonances near the optical absorption edge. One particular area of interest is in the changes in optical properties that can be induced by static electric fields; this is interesting both for the physical mechanisms involved, some of which are unique to quantum wells, and also the possibility of practical applications. The activity in both physics and applications of these other quantum well optical effects has been documented in a number of recent review articles'" and in some extensive journal articles, and we will not attempt to duplicate these here. Instead, we will present only a brief summary of some key topics and refer the reader to other longer articles for more detailed information. Because the layered structure of quantum wells quantum confines the carriers, the optical absorption spectrum breaks up into a series of steps. In addition, however, sharp peaks (the exciton absorption resonances) appear at the edges of the steps. These peaks are much stronger than those observed in the corresponding bulk materials, and can consequently be observed at room temperature. This strength is a direct consequence of the confinement (see e.g. Ref. 5 for a discussion) These peaks also show a number of interesting nonlinear optical effects associated with absorption saturation .415 AS for changes in optical properties associated with electric fields, there are obviously two distinct directions in which the electric field can be applied, i.e. parallel to the layers and perpendicular to the layers. For fields parallel to the layers, the resulting changes in the optical absorption near to the band gap energy are qualitatively similar to those seen in bulk direct gap semiconductors at low temperature; the exciton peaks broaden and disappear with field because the exciton is rapidly field ionized, leading to a life time broadening of the resonance.6 The fact that this phenomenon can be clearly observed in quantum wells at room temperature has made it feasible to perform very high speed tests of the speed of this electroabsorption, with response 500 fs observed,7 the fastest electroabsorption ever reported to our knowledge. For perpendicular field, the behavior is quite different; the peaks are not strongly broadened with field, and the lowest peaks shift to lower energy by substantial amounts. This effect can be understood through a mechanism called the quantum confined Stark effect (QCSE).6/8 m this case, the field ionization is suppressed by the walls of the quantum well, and very large Stark shifts of the exciton are possible without large broadening. In the limit where the excitonic effects are neglected, the resulting shifts reduce to the sum of the shifts of the single particle electron and hole shifts resulting from the skewing of the quantum well by the applied field. It is, however, important to remember that it is the persistence of the exciton resonance that gives the QCSE much of its practical interest and that enables us to resolve the shift at all. As the peaks shift, they lose some strength because the overlap of electron and hole is reduced as they are pulled apart by the field. Both the shifts*'deg and the overlap^ are in good agreement with theory. The strength lost by the allowed transitions is picked up by the appearance of forbidden transitions,9 which leads to the sum rules for the quantum well electroabsorption.9 The forbidden transitions are also important in linking the QCSE to bulk electroabsorption;10 in the simplifying approximation in which the excitonic effects are neglected (an approximation that we can refer to as the quantum confined Franz Keldysh approximation) it can be shown that the QCSE is the quantum confined limit of the Franz Keldysh electroabsorption of bulk semiconductors.
author_names: D A B Miller
title: Quantum wells have recently become increasingly
year: 2017

abstract: D. A. B. Miller et al. Physical Review Letters, vol. 53, No. 22, Nov. 26, 1984, "Band Edge Electroabsorption in Quantum Well Structures: The Quantum Confined Stark Effect," pp. 2173 2176. Y. Silberberg et al. Applied Physics Letters, vol. 46, No. 8, Apr. 15, 1985, "Fast Nonlinear Optical Response from Proton Bombarded Multiple Quantum Well Structure, pp. 701 703. M. Wegener et al. Applied Physics Letters, vol. 55, No. 6. Aug. 7, 1989, "Electroabsorption and Refraction by 73 Assignee:
author_names: Firm-Gregory C Ranieri
title: Fast Nonlinear Optical Response from Proton Bombarded Multiple Quantum Well Structure
year: 2017

abstract: In this chapter we overview recent achievements in the synthesis and investigation of optical properties of the new type of quantum sized semiconductor nanocrystals 2D nanoplatelets. Thin, atomically flat AIIBVI nanoplatelets prepared by colloidal chemistry routes are good model objects for studying optical properties of 2D semiconductor structures. Due to their discrete thickness, nanoplatelets exhibit spectrally narrow excitonic optical transitions in absorption and photoluminescence. Large lateral size of semiconductor nanoplatelets results in very efficient light absorption with the molar absorption coefficient an order of magnitude greater than that of 0D quantum dots and 1D nanorods. Sharp excitonic absorption bands of CdSe nanoplatelets allow observation of large electro optical Quantum Confined Stark effect which is much stronger than in the corresponding nanorods, or quantum dots. Besides binary core CdSe, CdS, CdTe nanoplatelets, more complex CdSe/CdS core shell and unique core wings CdSe CdS, CdSe CdTe and CdTe CdSe heteronanoplatelets with type I and type II optical transitions and bright photoluminescence can be synthesized. This expands the field of potential practical applications of nanoplatelets as efficient light convertors and fluorescent markers even further.
author_names: Artsiom Antanovich

Anatol V Prudnikau

Mikhail V Artemyev
title: Optical Properties of Semiconductor Colloidal Quantum Wells
year: 2016

abstract: Vertical cavity surface emitting lasers (VCSELs) are promising in various applications including full color mobile projectors, laser precision processing, display, armarium and high speed air water optical wireless communication system with a unique combination of advantages. However, GaN based VCSELs with emission wavelengths in green are challenging because of the low emission efficiency of green emitting InGaN QWs. This is well known as the "Green Gap" which is mainly caused by Quantum Confined Stark effect (QCSE) and the high density of defects and dislocations. In this paper, we would like to discuss the origin of "green gap" and possible approaches to overcome it, and then review our recent progress in green VCSELs: (1) Lasing from 479.6 nm to 565.7 nm by using QD active area (2) Lasing at 545 nm by using QD in QW active structure; (3) Lasing at 493 nm by utilizing blue emitting InGaN QWs with the combination of cavity effect.
author_names: Huan Xu

Yang Mei

Xu Rongbin

Leiying Ying

Xuliang Su

Jianping Liu

Baoping Zhang
title: Green VCSELs based on nitride semiconductors
year: 2020

abstract: Abstract. There have been recent research advances in AlGaN based self assembled nanowires (NWs) as building blocks for ultraviolet (UV) optoelectronics grown by plasma assisted molecular beam epitaxy. We review the basic growth kinetics on various foundry compatible metal/silicon based substrates and the epistructure design for UV devices. We highlight the use of diffusion barrier metal thin film on silicon substrate as a solution to enhance device performance. NWs offer the opportunity to mitigate the detrimental quantum confined Stark effect (QCSE) which lowers the recombination rate thereby reducing the device efficiency. On the other hand, the polarization induced doping from the graded composition along NWs can be advantageous for eluding the inefficient doping in AlGaN based UV devices. Sidewall surface states and the associate passivation treatment, as well as the use of ultrafast electron microscopy characterization, are crucial investigations in shedding light on device performance under the influence of surface dangling bonds. For investigating the electrical performance of individual NWs and NWs light emitting diode as a single entity, recent reports based on conductive atomic force microscopy measurements provide fast prototyping in process pass fail evaluation and a means of improving growth for high performance devices. Stress tests of NWs devices, crucial for reliable operation, are also discussed. Beyond applications in LEDs, an AlGaN based NWs solar blind photodetector demonstrated leveraging on the dislocation free active region, reduced QCSE, enhanced light absorption, and tunable composition features. The review opens pathways and offers insights for practical realization of AlGaN based axial NWs devices on scalable and low cost silicon substrates.
author_names: Jung-Wook Min

Davide Priante

Malleswararao Tangi

Guangyu Liu

Chun Hong Kang

Aditya Prabaswara

Chao Zhao

Latifah Al-Maghrabi

Yazeed Alaskar

A M Albadri

Ahmed Y Alyamani

Tien Khee Ng

Boon Siew Ooi
title: Unleashing the potential of molecular beam epitaxy grown AlGaN based ultraviolet spectrum nanowires devices
year: 2018