Band energy diagrams

Instead of plotting tire electron distribution function in tire energy band diagram, it is convenient to indicate tire position of tire Fenni level. In a semiconductor of high purity, tire Fenni level is close to mid-gap. In p type (n type) semiconductors, it lies near tire VB (CB). In very heavily doped semiconductors tire Fenni level can move into eitlier tire CB or VB, depending on tire doping type. 

Figure C2.16.7. A schematic energy band diagram of a p-n junction witliout external bias (a) and under forward bias (b). Electrons and holes are indicated witli - and + signs, respectively. It should be remembered tliat tlie energy of electrons increases by moving up, holes by moving down. Electrons injected into tlie p side of tlie junction become minority carriers. Approximate positions of donor and acceptor levels and tlie Feniii level, are indicated.

Figure C2.16.8. Schematic energy band diagram for an n-p-n bipolar junction transistor. Positions of quasi-Fenni levels and bias voltages are indicated.

Fig. 1. Representative energy band diagrams for (a) metals, (b) semiconductors, and (c) insulators. The dashed line represents the Fermi Level, and the shaded areas represent filled states of the bands. denotes the band gap of the material.

Fig. 2. (a) A schematic diagram of a n—p junction, including the charge distribution around the junction, where 0 represents the donor ion 0, acceptor ion , electron °, hole, (b) A simplified electron energy band diagram for a n—p junction cell in the dark and in thermal equilibrium under short-circuit... 

Figure 21. The energy band diagram (only the conduction band is shown) calculated for the silicon/electrolyte interface with a potential drop of 5 V and different radii of curvature. Ec is the conduction bandedge in the bulk and Ecs is the conduction bandedge at the surface. AE AEj, AE1/2, and AE1/5 are the possible tunneling energy ranges for different radii of curvature. The distribution of occupied states at the interface, Dred, is also schematically indicated. After Zhang.24...

Electrochemical Cell Configuration Corresponding Energy-Band Diagrams... 

Figure 12.24. PIN photodiode, (a) Fabrication, (b) Energy band diagram, (c) Absorption in the depletion layer.

Fig. 16.7 Energy-band diagrams of DSSCs with incorporated (a) semiconducting (s-) SWCNTs and (b) metallic (m-) SWCNTs. The solid and dashed arrows represent desired charge transport and undesired recombination processes. Adapted from Guai etal. [95].

Figure 1.12. Energy band diagram illustrating the definitions used.

Figure 4.27. (a) Schematic of a STM z- Ft injection spectrum (solid curve). The dashed curves represent typical STM tip displacements observed at a clean metal surface, (b) Energy band diagrams for STM tunnelling through a vacuum barrier into the organic thin film and (c) through a Schottky-like barrier with the tip in contact. In both cases, Ft < 0 relative to Ep is shown. Adapted from Muller et al, 2001. 

Fig. 29 (a) Architecture of graphene based OLED. (b) Energy band diagram of the device. (Reprinted with permission from [260])... 

Figure 1.15 Energy band diagram for a sodium lattice. From K. M. Ralls, T. H. Courtney, and J. Wulff, Introduction to Materials Science and Engineering. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc. After J. C. Slater, Phys. Rev., 45, 794 (1934).

Figure 6.12 (a) Orbitals in the (100) plane of rocksalt structure showing cation-cation and cation-anion-cation interaction (b) schematic energy band diagram of TiO. 

Fig. 2. Schematic energy band diagrams showing the use of a p -n junction to study capture and emission processes at a deep level. The junction is shown at steady state with a reverse bias of V volts (a) and with 0 volts (b). The width of the space-charge region under these conditions is ) and WTO). Immediately after the reverse bias is switched from 0 to V volts a nonequilibrium condition exists in which electrons occupying traps within the space-charge region are emitted to the conduction band and swept out (c). The shallow donor and acceptor that must be present have been omitted for clarity.

The energy band diagram for Ti02 in pH 7 solution is shown in Fig. 2.7. As shown, the redox potential for photogenerated holes is +2.53 V vs. the standard hydrogen electrode (SHE). After reaction with water, these holes can produce hydroxyl radicals ( OH), whose redox potential is only slightly decreased. Both are more positive than that for ozone. The redox potential for conduction band... 

Fig. 4.11 Energy band diagrams for metal-loaded Ti02 particles (photocatalyst). (A) The metal acts as a catalyst for a reductive reaction such as hydrogen evolution under weak band bending. (B) The metal acts as a catalyst for an oxidative reaction such as oxygen evolution under strong band bending.

Fig. 4.10 Two-dimensional energy band diagram for a metal dot-coated n-type semiconductor electrode.

Figure 2. Energy band diagram of the CdSe-SrTiOs composite electrodes (A refers to CdSe and B to SrTiO,)...

Figure 4. Energy band diagrams (after Ref. 4) for TiOt, VO-2, and MoO,...

Figure I. (a) Schematic diagram of a metal/insulator/metal tunnel junction with a variable applied d.c. bias voltage, (b) Partial schematic energy band diagram under zero applied bias conditions, where j and s are the mean barrier height and thickness respectively, (c) Corresponding energy-band diagram where applied dx. bias V is sufficient to excite a vibrational mode in the barrier thus producing an inelastic tunneling current.

Figure 8. Schematic representations of p-n junctions and corresponding energy band diagrams under various conditions (a) uniformly doped p-type and n-type semiconductors before junction is formed, (b) thermal equilibrium, (c) forward bias, and (d) reverse bias. Abbreviations are defined as follows Ec, electron energy at conduction band minimum E, , electron energy at valence band minimum IF, forward current Vf, forward voltage Vr, reverse voltage ...

Figure 13. Energy band diagrams and charge distributions of an ideal MOS capacitor using p-type Si (a) accumulation, (b) depletion, and (c) inversion. Ef denotes the intrinsic Fermi level. (Reproduced mth permission from reference 8. Copyright 1985 Wiley.)...

A Schottky barrier junction is constructed by, for example, depositing Pd on n-CdS (Seker et al 2000). Its simplified energy band diagram is shown in Fig. 9.21 together with a voltage source that applies a suitable bias across the diode. 

Figure 1. Schematic of a C-S diode. (A) physical configuration (B) energy band diagram in thermodynamic equilibrium (zero bias) and under forward bias.

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