Semiconductor Related Performance

Primarily connected to corrosion concepts, Pourbaix diagrams may be used within the scope of prediction and understanding of the thermodynamic stability of materials under various conditions. Park and Barber [25] have shown this relevance in examining the thermodynamic stabilities of semiconductor binary compounds such as CdS, CdSe, CdTe, and GaP, in relation to their flat band potentials and under conditions related to photoelectrochemical cell performance with different redox couples in solution. 

A thorough insight into the comparative photoelectrochemical-photocorrosion behavior of CdX crystals has been motivated by the study of an unusual phenomenon consisting of oscillation of photocurrent with a period of about 1 Hz, which was observed at an n-type CdTe semiconductor electrode in a cesium sulfide solution [83], The oscillating behavior lasted for about 2 h and could be explained by the existence of a Te layer of variable width. The dependence of the oscillation features on potential, temperature, and light intensity was reported. Most striking was the non-linear behavior of the system as a function of light intensity. A comparison of CdTe to other related systems (CdS, CdSe) and solution compositions was performed. 

The degree of activation of the sample is measured by post-irradiation spectroscopy, usually performed with high-purity semiconductors. The time-resolved intensity measurements of one of the several spectral lines enables to get the half-life of the radioactive element and the total number of nuclear reactions occurred. In fact, the intensity of a given spectral line associated with the decay of the radioactive elements decreases with time as Aft) = Aoexp[—t/r], where Aq indicates the initial number of nuclei (at t = 0) and r is the decay time constant related to the element half-life (r = In2/ /2), which can be measured. Integrating this relation from t = 0 to the total acquisition time, and weighting it with the detector efficiency and natural abundance lines, the total number of reactions N can be derived. Then, if one compares this number with the value obtained from the convolution of... 

Ruorinated thermoplastics are only used for high-performance applications related to their high heat, low temperature, chemical inertness, high purity, non-stick and self-lubricating properties. High-purity grades are appreciated by the semiconductor, pharmaceutical and other similar sectors. 

Roichman Y, Tessler N (2002) Generalized Einstein relation for disordered semiconductors -implications for device performance. Appl Phys Lett 80 1948... 

Until recently, most reported evaluations and analyses of SiC components, as they relate to circuit performance, have been limited to p-/-n and Schottky diodes. This has been due to both the complexity of the analyses and availability of stable components. In the previous discussions, it was noted that a variety of techniques have been employed to expand the operating regime of Si-based switching converters by ameliorating the electrical stress. The introduction of commercially available SiC semiconductor components by Infineon and Cree have raised the question of how SiC technology will impact the next generation of switching power circuits. 

The fabrication of active semiconductor devices from amorphous semiconductor films is a further application that offers considerable advantages. Thin-fihn transistors, based on amorphous films of hydrogenated silicon, are nnder intensive development. Other devices with monostable and bistable switching characteristics have also received considerable interest. Naturally enough, the performance of snch devices is intimately related to the transport properties of charge carriers in the materials employed. 

However, the key components to provide the power generating functionality are based on semiconductors. Novel materials and transistor structures based on InP, SiGe and GaN represent an area of extensive R D activities with emphasis on high power, low noise and high operation frequencies. The performance of a real device such as the phase noise of a microwave oscillator depends both on the noise properties of the transistor and on the loss tangent of the oxide material which forms the stabilising resonator. Therefore, material and device related R D activities both on semiconductors and on oxides are essential to open new horizons for microwave communication and sensor applications. 

In addition to improving structural order, reliable improvements of device performance have been demonstrated through optimization of device interfaces and architectures. The architectures are perhaps more easily addressed, and are also related to improving the structural order. Several possible constructions of TFT are known from the long history of silicon-based devices. These were the first architectures adopted for OTFTs also. Top and bottom contact, indicating the location of the source and drain electrodes with regard to the semiconductor, are the most widely used. 

Other than the mutually photosensitive components, coupling between one photosensitive and another nonsensitive (e.g., very wide bandgap) semiconductor may also have positive effects on the photocatalytic performance of the sensitive one. For example, Kisch and Weiss (Weiss et al. 2001 Kisch and Weiss 2002) studied the Si02-supported CdS photoelectrode in an organic addition reaction, and found that the enhanced photocatalytic activity was related to the changes in bandgap and flat-band potential of CdS, which originates from an electronic semiconductor-support interaction mediated by [SiJ-O-Cd-S bonds. 

---