Solid-state junctions junction fabrication

The selection made covers the first efficient and stable system based on the ternary chalcopyrite CulnSe2, an electrochemical treatment to avoid a toxic etching step in solid-state CIS device fabrication, the first stable and efficient liquid-junction solar cell (InP), and a novel concept where nanoemitters, interspersed in a nanoporous passivating film, are used to scavenge excess minority carriers. 

The status of the dye-sensitized device as the only verified alternative to solid-state junction devices has already been discussed. It must be recognized that the solid-state devices, particularly the silicon p-n junction cells benefit from forty years of industrial and development experience, the technology transfer from the silicon-based electronics industry, and even the widespread availability of high-quality silicon at low cost resulting from the expansion of that industry. The procedures for high-yield fabrication of silicon devices, both crystalline and amorphous, are well understood, with costing well established on the basis of decades of solid industrial experience. For dye-sensitized... 

Recently, RBS has been used to study the metal-silicon reactions induced by both a CW laser and an electron beam (53). Uniform, large area, single phase silicides were formed by adjusting the beam power level to induce a solid state reaction. Under certain conditions metastable mixed-phase systems were also obtained. RBS could non-destructively determine the stoichiometry of the phases formed without additional standards. AES and SIMS have also been used in the study of metal silicides. These applications and other points of interest in the fabrication, characterization and application of metal-semiconductor Schottky barrier junctions have been reviewed recently by Sharma and Gupta (54). 

Current fabrication schemes for solid-state three-terminal molecular junctions typically rely on electromigration [78] to produce a nanoscale gap between two metallic electrodes which rests on top of a gate electrode, separated by a thin oxide layer. A schematic representation of a three-terminal device is shown in Fig. 10.15. 

Preliminary results were recently reported [145] on the use of CdTe electrodeposition on diamond in the fabrication of a solid-state solar cell based on the boron-doped p-type diamond/n-type CdTe junction. In this cell, the wide-bandgap diamond is an optical window that generates photovoltage, whereas the narrow-bandgap CdTe generates photocurrent. We note that no appropriate p-type material for the fabrication of optical windows has existed so far therefore, one would use an n-type CdS window coupled with narrow-bandgap p-type CdTe. However, the pro-... 

Even though the field-effect transistor did not come into widespread use until the 1960 s, its invention predated both the junction and point-contact transistors by many years. As it is normal with many innovations, its practical realization was delayed until adequate materials and technologies were available for its fabrication. We can even say that the Thin Film Transistor (TFT) was the first solid-state amplifier ever patented. The basic principle of the field-effect transistor (what we call now JFET) was proposed by the first time by Julius Edgar Lilienfeld as early as 1925 and patented in 1930 Ref (1) (see Fig. la) where an adaptation of the cross section of the... 

In spite of impressive experimental demonstrations of basic quantum information effects in a number of different mesoscopic solid state systems, such as quantum dots in semiconductor microcavities, cold ions in traps, nuclear spin systems, Josephson junctions, etc., their concrete implementation is still at the proof-of-principle stage [1]. The development of materials that may host quantum coherent states with long coherence lifetimes is a critical research problem for the nearest future. There is a need for the fabrication of quantum bits (qubits) with coherence lifetimes at least three-four orders of magnitude longer than it takes to perform a bit flip. This would involve entangling operations, followed by the nearest neighbor interaction over short distances and quantum information transfer over longer distances. 

Mattei G, Valentini V (2003) In situ functionalization of porous silicon during the electrochemical formation process in ethanoic hydrofluoric acid solution. J Am Chem Soc 125 9608-9609 McGiimis S, Sines P, Das B (1999) Pulsed current anodization an effective method for fabricating patterned porous silicon p-n junction light-emitting diodes. Electrochem Solid State Lett... 

An LED is a specific type of solid-state diode, but it stiU retains the other properties typical of diodes. Solid-state diodes are formed at the junction of two semiconductors of different properties. Semiconductors are materials that are inherently neither good conductors nor good insulators. The electrical properties of the materials making up semiconductors can be altered by the addition of impurities into the crystal structure of the material as it is fabricated. Adding impurities to semiconductors to achieve the proper electrical nature is called doping. If the added impurity has one more electron in its outermost electron shell compared with the semiconductor material, then extra electrons are available to conduct electricity. This is a negative doped, or n-type, semiconductor. However, if the impurity has one fewer electron in its outermost electron shell compared with the semiconductor material, then there are too few electrons in the crystal structure, and an electron... 

A film of electroactive polymer [Os(bpy)2(vpy)2p, sandwiched between Pt and Au electrodes, becomes conductive when both the electrode potentials have appropriate values such that the mixed valent state, Os(III)/(II), is generated. Such arrangements are used in two-terminal and three-terminal diodes Solid-state organic heterojunctions utilizing two conducting polymers [PA and poly(A-methylpyrrole) junctions] were reported The electronic properties can be modified chemically. A field-effect transistor was fabricated utilizing chemically prepared poly(A-methyl-pyrrole)... 

Liquid-junction photovoltaic cells have advantages in their simplicity and ease of fabrication, as described before. Solid-state devices can also be constructed from liquid-junction cells when a solid polymer electrolyte is used. A tandem photovoltaic... 

The absence of solvents in such solid-polymer-electrolyte photovoltaic cells presents the possibility of fabricating corrosion-free systems. The thin-film solid-state cells also allow fabrication of multispectral cells composed of more than one semiconductor in optical and electrical series. A solid-state photovoltaic cell, n-Si/Pt/PP/PEO(K.I/ l2)/Pt/ITO, was studied. The surface modifications of n-Si with PP can dramatically reduce the large activation energy barrier against efficient charge transfer between semiconductor and polymer-solid electrolyte. The efficiency of this cell is limited by a high surface recombination velocity associated with surface states of the n-Si. The cell had V = 225 mV and 11 niA cm at 100 mW cm illumination with junction ideality factor of 1.5. This implies the existence of deleterious surface states acting as recombination centres. 

Thermoelectric coolers (TEC) are solid-state heat pumps based upon the Peltier effect without any fluids or moving mechanical parts. In the Peltier effect, a potential is applied to two junctions as shown in Figure 3.15. Heat will be expelled from one junction and absorbed into the other in an amount proportional to the applied current. The thermoelectric cooler consists of an array of junctions using bismuth telluride (Bi2Te3), lead telluride (PbTe), or silicon germanium (SiGe). These materials are doped during fabrication to optimize the parameters of the cooler. Bismuth telluride has been found to have the best performance and is widely used for thermoelectric coolers. 

For nonaqueous electrochemistry, lUPAC recommended the use of a redox couple such as ferrocene/ferrocenium ion (Fc/Fc" ) as an internal standard [26]. An alternative to the liquid junction electrode is one based on an entirely solid-state design. Peerce and Bard [27] fabricated such an electrode by coating poly (vinylferrocene) (PVFc) on platinum. The polymer-coated electrode was brought to a 1 1 ratio of ferrocene to ferrocenium by poising the electrode at the PVTc/Fc" half-wave potential (0.39 V vs. SCE). Although this electrode maintained a constant, reproducible potential in deaerated acetonitrile over 21 h, it was unstable in other... 

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