Few Related Applications and Brief Review of Experimental Results
01 Jan 2015-pp 371-396
TL;DR: The concept of band gap measurement in the presence of intense external light waves is discussed and additional five related applications in this context are presented.
Abstract: The concept of band gap measurement in the presence of intense external light waves is also discussed and we present additional five related applications in this context. Besides, the experimental aspects of the EP from quantized structures have also been discussed very briefly. This chapter contains a single multi-dimensional deep open research problem.
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01 Jan 1991TL;DR: In this paper, the authors present a survey of reliability issues in semiconductors, metals, thin films and coatings, and thin-film and coating applications, and stress-strain and fracture analysis.
Abstract: Part I. Metals Part II. Organic Materials Part III. Semiconductors Part IV. Thin Films and Coatings Part V. Stress-Strain and Fracture Analyses Part VI. Reliability Issues.
23 citations
References
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TL;DR: In this paper, free standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithography using electrochemical and chemical dissolution steps to define networks of isolated wires out of bulk wafers.
Abstract: Indirect evidence is presented that free‐standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithography. The novel approach uses electrochemical and chemical dissolution steps to define networks of isolated wires out of bulk wafers. Mesoporous Si layers of high porosity exhibit visible (red) photoluminescence at room temperature, observable with the naked eye under <1 mW unfocused (<0.1 W cm−2) green or blue laser line excitation. This is attributed to dramatic two‐dimensional quantum size effects which can produce emission far above the band gap of bulk crystalline Si.
7,393 citations
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TL;DR: In this article, a hybrid organic/inorganic electroluminescent device was constructed based on the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV) with electrons injected into the multilayer film of cadmium selenide nanocrystals.
Abstract: ELECTROLUMINESCENT devices have been developed recently that are based on new materials such as porous silicon1 and semiconducting polymers2,3. By taking advantage of developments in the preparation and characterization of direct-gap semiconductor nanocrystals4–6, and of electroluminescent polymers7, we have now constructed a hybrid organic/inorganic electroluminescent device. Light emission arises from the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV)8–10 with electrons injected into a multilayer film of cadmium selenide nanocrystals. Close matching of the emitting layer of nanocrystals with the work function of the metal contact leads to an operating voltage11 of only 4V. At low voltages emission from the CdSe layer occurs. Because of the quantum size effect19–24 the colour of this emission can be varied from red to yellow by changing the nanocrystal size. At higher voltages green emission from the polymer layer predominates. Thus this device has a degree of voltage tunability of colour.
3,783 citations
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TL;DR: In this article, a hybrid organic/inorganic electroluminescent device was constructed based on the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV) with electrons injected into the multilayer film of cadmium selenide nanocrystals.
Abstract: ELECTROLUMINESCENT devices have been developed recently that are based on new materials such as porous silicon' and semiconducting polymers 2,3 . By taking advantage of developments in the preparation and characterization of direct-gap semiconductor nanocrystals 4-6 , and of electroluminescent polymers7, we have now constructed a hybrid organic/inorganic electroluminescent device. Light emission arises from the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV) 2-10 with electrons injected into a multilayer film of cadmium selenide nanocrystals. Close matching of the emitting layer of nanocrystals with the work function of the metal contact leads to an operating voltage" of only 4 V. At low voltages emission from the CdSe layer occurs. Because of the quantum size effect 19-24 the colour of this emission can be varied from red to yellow by changing the nanocrystal size. At higher voltages green emission from the polymer layer predominates. Thus this device has a degree of voltage tunability of colour.
3,285 citations
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TL;DR: In this article, it was shown that a two-dimensional quantum confinement (quantum wire) in the very narrow walls between the pores not only explains the change in band gap energy but also may also explain the dissolution mechanism that leads to porous silicon formation.
Abstract: Porous silicon layers grown on nondegenerated p‐type silicon electrodes in hydrofluoric acid electrolytes are translucent for visible light, which is equivalent to an increased band gap compared to bulk silicon. It will be shown that a two‐dimensional quantum confinement (quantum wire) in the very narrow walls between the pores not only explains the change in band‐gap energy but may also be the key to better understanding the dissolution mechanism that leads to porous silicon formation.
1,705 citations
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TL;DR: In this paper, the structure of the porous layers that emit red light under photoexcitation was revealed, which constitutes direct evidence that highly porous silicon contains quantum-size crystalline structures responsible for the visible emission.
Abstract: LIGHT-emitting devices based on silicon would find many applications in both VLSI and display technologies, but silicon normally emits only extremely weak infrared photoluminescence because of its relatively small and indirect band gap1. The recent demonstration of very efficient and multicolour (red, orange, yellow and green) visible light emission from highly porous, electrochemically etched silicon2,3 has therefore generated much interest. On the basis of strong but indirect evidence, this phenomenon was initially attributed to quantum size effects within crystalline material2, but this interpretation has subsequently been extensively debated. Here we report results from a transmission electron microscopy study which reveals the structure of the porous layers that emit red light under photoexcitation. Our results constitute direct evidence that highly porous silicon contains quantum-size crystalline structures responsible for the visible emission. We show that arrays of linear quantum wires are present and obtain images of individual quantum wires of width <3 nm.
1,285 citations