Lateral quantization effects in lithographically defined CdZnSe/ZnSe quantum dots and quantum wires

Illing, M.; Bacher, G.; Kümmell, T.; Forchel, A.; Andersson, T. G.; Hommel, D.; Jobst, B.; Landwehr, G.

doi:10.1063/1.115504

Cited by 62 publications

(25 citation statements)

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“…In order to suppress any influence of spatial diffusion of excitons, quantum dots were fabricated by electron beam lithography and wet chemical etching using a K 2 Cr 2 O 7 : HBr : H 2 O solution. This technique ensures quantum dots of high optical quality with a lateral extension of 35 nm [4]. In Fig.…”

Section: Resultsmentioning

confidence: 99%

Relaxation of hot excitons in CdZnSe/ZnSe quantum wells and quantum dots

Spiegel

Bacher

Breitwieser

et al. 1998

Superlattices and Microstructures

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Section: Resultsmentioning

confidence: 99%

Relaxation of hot excitons in CdZnSe/ZnSe quantum wells and quantum dots

Spiegel

Bacher

Breitwieser

et al. 1998

Superlattices and Microstructures

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“…Comparing the average number of peaks per spectrum with the 2.5x10" cm2 excitation spot, we conclude that the excitons giving rise to this emission are confined in an area scaling with the exciton Bohr radius (5 tim). This is markedly smaller than the characteristic dimensions of(Zn,Cd)Se quantum dots defined by lithography and etch techniques [8]. Xin et al [9] have reported on the molecular beam epitaxial growth of self-assembled Il-VI dots of pure CdSe and succeeded to image these dots directly by AFM.…”

Section: Growfh and Characterizationmentioning

confidence: 99%

<title>Self-assembled visible-bandgap II-VI quantum dots</title>

Lowisch

Rabe

Stegemann

et al. 1997

Physics and Simulation of Optoelectronic Devices V

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This paper reports on the self-assembled growth of Il-VI semiconductor quantum dots by molecular beam epitaxy. The dots are formed in a highly-strained (Zn,Cd)Se film of only a few monolayer width grown on ZnSe. The formation sets on when the CD mole fraction exceeds 30 %. We present data on the recombination and relaxation of carriers and excitons in these zero-dimensional structures as well as their interaction with phonons.keywords: quantum dots, (Zn,Cd)Se, ZnSe, luminescence, phonons, confined excitons, MBE growth 1. ENTRODUCTION Wide-gap 11-Vt heterostructures are promising candidates for the fabrication of visible-wavelength opto-electronic and photomc devices. In recent years, semiconductor quantum dots have attracted particular interest. There are various predictions that these zero-dimensional structures exhibit a number of extraordinary properties, making them especially useful for light emitting devices, modulators, or switches. However, despite of extensive efforts, many of these predictions have not been confirmed experimentally so far. This is partly caused by an insufficient sample quality (large homogeneous and itthomogeneous broadening, surface states, low radiative yield,...) and partly by inappropriate theoretical approaches.Recent work on 111-V materials, e.g. (In,Ga)As, has demonstrated that quantum dots can be directly fabricated by molecular beam epitaxy utilizing self-organization [1]. One example is the Stranski-Krastanov mechanism, where strain relaxation turns the growth from an initially two-dimensional into a three-dimensional one. This allows to apply purity and quality standards inherent in epitaxial growth. By definition, in a "true" quantum dot, the carriers (electron and holes) are confined in a volume that is comparable with the excitonic Bohr radius. In this situation, concepts successfully used to understand the physics of bulk or quantum well devices, are no longer valid. Ultimately, the electron-hole Coulomb interaction will play a key role. The laser action of quantum dots is one example, where this is readily seen. Instead of an electron-hole plasma, bi-excitons are carrying the optical gain [2][3][4]. It is obvious from Table 1, comparing exciton and bi-exciton binding energies for (Zn,Cd)Se and (In,Ga)As, that Il-VI quantum dots will provide much more direct experimental access to the relevant processes (though the underlying physics in Ill-V structures is qualitatively the same). Therefore, in addition to their visible band-gap, Il-VI quantum dots are also ideal candidates to study various fundamental aspects of zero-dimensional semiconductor structures. SPIE Vol. 2994 • 0277-786X197/$1 0.00 43 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/27/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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“…Usually, the pattern defined by lithography is transferred into the semiconductor by wet or dry etching techniques and a variety of processes have been developed for II-VI materials. 5,[9][10][11] However, this technique suffers from the formation of etched sidewalls, where usually nonradiative recombination occurs. This reduces the quantum efficiency in quantum wires and dots 5 as well as in laser diodes.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8][9] This is a consequence of the feasibility of lithographic techniques to design not only the lateral size and shape of the micro-and nanostructures, but also to define periodic or laterally ordered structures. Usually, the pattern defined by lithography is transferred into the semiconductor by wet or dry etching techniques and a variety of processes have been developed for II-VI materials.…”

Section: Introductionmentioning

confidence: 99%

Selective ultrahigh vacuum dry etching process for ZnSe-based II–VI semiconductors

Legge

Bacher

Bäder

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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A selective dry etching technique for II–VI semiconductors based on ZnSe has been developed by using thermally assisted electron cyclotron resonance etching with a gas mixture of Ar, Cl2, and BCl3. While the etching process is found to be almost nonselective between ZnSe and MgZnSSe at low (<100 °C) and high (>220 °C) substrate temperatures, a strong selectivity is obtained in the intermediate temperature range (e.g., 12:1 for Tsub=180 °C). Due to the ultrahigh vacuum (UHV) design of the etching chamber, a complete in situ fabrication of buried II–VI nanostructures should be accessible.

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Lateral quantization effects in lithographically defined CdZnSe/ZnSe quantum dots and quantum wires

Cited by 62 publications

References 0 publications

Relaxation of hot excitons in CdZnSe/ZnSe quantum wells and quantum dots

Relaxation of hot excitons in CdZnSe/ZnSe quantum wells and quantum dots

<title>Self-assembled visible-bandgap II-VI quantum dots</title>

Selective ultrahigh vacuum dry etching process for ZnSe-based II–VI semiconductors

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