Semiconductor nature

In addition, Janczak [26] studied the conductivity property of complex 3 with a polycrystalline sample, and the results show that the conductivity is in the range 2.7 -2.8 x 10-2Q-1cm-1 at room temperature. Very weak temperature dependence of the conductivity and a metallic-like dependence in conductivity are observed in the range 300-15 K. Ibers and co-workers [70] investigated the electrical conductivity of partially oxidized complex 82 with a suitable single crystal and the results indicate its semiconductor nature (Ea = 0.22eV). 

Nomura, K. Ohta, H. Takagi, A. Kamiya, T. Hirano, M. Hosono, H. 2004. Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors. Nature 432 488-492. 

Inokuchi H, Imaeda K, Enoki T, Mori T, Maruyama Y, Saito G, Okada N, Yamochi H, Seki K, Higuchi Y, Yasuoka N (1987) Tetrakis(methyltelluro)tetrathiafulvalene (TTeCjTTF), a high-mobility organic semiconductor. Nature 329 39 0... 

Chua L-L, Zaumseil J, Chang J-F, Ou EC-W, Ho PK-H, Sirringhaus H, Friend RH (2005) General observation of n-type field-effect behaviour in organic semiconductors. Nature 434 194-1999... 

While considering trends in further investigations, one has to pay special attention to the effect of electroreflection. So far, this effect has been used to obtain information on the structure of the near-the-surface region of a semiconductor, but the electroreflection method makes it possible, in principle, to study electrode reactions, adsorption, and the properties of thin surface layers. Let us note in this respect an important role of objects with semiconducting properties for electrochemistry and photoelectrochemistry as a whole. Here we mean oxide and other films, polylayers of adsorbed organic substances, and other materials on the surface of metallic electrodes. Anomalies in the electrochemical behavior of such systems are frequently explained by their semiconductor nature. Yet, there is a barrier between electrochemistry and photoelectrochemistry of crystalline semiconductors with electronic conductivity, on the one hand, and electrochemistry of oxide films, which usually are amorphous and have appreciable ionic conductivity, on the other hand. To overcome this barrier is the task of further investigations. 

Actually, the electrochemistry of diamond dates back to the paper [11], A current-voltage curve of crystalline diamond electrode was first taken there, as well as the differential capacitance measured at the diamond/electrolyte solution interface. The diamond electrodes turned out to be photosensitive, and their photo-electrochemical behavior was compared with their semiconductor nature. 

Two features manifest themselves in the impedance behavior of diamond electrodes, namely, the effects of semiconductor nature of diamond (with moderately doped films) and a specific type of frequency dependence of impedance, which is characteristic of a great majority of films. 

The semiconductor nature of diamond manifests itself in a photoelectrochemical response caused by the photogeneration of free charge carriers. With the dielectric diamond, photoconductance (that is, an increase in the conductance due to an increase in majority carrier concentration) can be observed. With the conducting... 

Figure 4. Influence of semiconductor nature on the chemoselectivity of lactic acid photo-oxidation.

Schnadt J., Bruehwiler P. A., Patthey L., O Shea J. N., Soedergren S., Odelius M., Ahuja R., Karis O., Baessler M., Persson P., Siegbahn H., Lunell S. and Martensson N. (2002), Experimental evidence for sub-3-fs charge transfer from an aromatic adsorbate to a semiconductor . Nature 418, 620-623. 

Inoue, T. Fujishima, A. Konishi, S. Honda, K. Photoelectrocata-lytic reduction of carbon dioxide in aqueous suspensions of semiconductor. Nature, 1979, 277, 637 - 638. 

Chua, L. et al., General observation of -type field effect behavior in organic semiconductors, Nature 434, 194—199, 2005. 

In reality, the measured ( )m comprises two parts the bulk contribution to the work function or the internal work function, ( )n,b, and a surface electric dipole Aq associated with the tail of the electron wave function spilling out of metal surface into vacuum, as depicted in Figure 6.3. Thus, the work function of metal is in fact a parameter characterized by the metal/vacuum interface. When the metal comes in contact with an organic semiconductor, naturally the dipole... 

A. Kohler, D.A. dos Santos, D. Beljonne, Z. Shuai, J.L. Bredas, A.B. Holmes, A. Kraus, K. Mullen, and R.H. Friend, Charge separation in localized and delocalized electronic states in polymeric semiconductors. Nature, 392, 903-906 (1998). 

The absolute values and the nature of the tenq)erature dependences of tiie thermoelectric properties of iron mon-osilicide (Fig. 1) indicate that it is a semiconductor below room temperature and a metal at higher temperatures the calculated value of the activation energy of the carriers is about 0.05 ev (data on the semiconductor nature of the temperature dependence of Upesi 1° good agreement with results in [17], althou the value AE 0.5 eV quoted in [17] is incorrect). 

Pemstich, K.P., Rossner, B., Batlogg, B., 2008. Field-effect-modulated seebeck coefficient in organic semiconductors. Nature Materials 7, 321—325. 

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