Schottky barrier

About: Schottky barrier is a research topic. Over the lifetime, 22570 publications have been published within this topic receiving 427746 citations. The topic is also known as: Schottky barrier junction.

Advanced Theory of Semiconductor Devices

Abstract: Preface. Acknowledgments. A Brief Review of the Basic Equations. The Symmetry of the Crystal Lattice. The Theory of Energy Bands in Crystals. Imperfections of Ideal Crystal Structure. Equilibrium Statistics for Electrons and Holes. Self--Consistent Potentials and Dielectric Properties. Scattering Theory. The Boltzmann Transport Equation. Generation--Recombination. The Heterojunction Barrier. The Device Equations of Shockley and Stratton. Numerical Device Simulations. Diodes. Laser Diodes. Transistors. Future Semiconductor Devices. Appendix A: Tunneling and the Golden Rule. Appendix B: The One Band Approximation. Appendix C: Temperature Dependence of the Band Structure. Appendix D: Hall Effect and Magnetoresistance. Appendix E: The Power Balance Equation. Appendix F: The Self--Consistent Potential at a Heterojunction. Appendix G: Schottky Barrier Transport. Index. About the Author.

Quantum Dot Size Dependent J-V Characteristics in Heterojunction ZnO/PbS Quantum Dot Solar Cells

Abstract: The current−voltage (J−V) characteristics of ZnO/PbS quantum dot (QD) solar cells show a QD size-dependent behavior resulting from a Schottky junction that forms at the back metal electrode opposing the desirable diode formed between the ZnO and PbS QD layers. We study a QD size-dependent roll-over effect that refers to the saturation of photocurrent in forward bias and crossover effect which occurs when the light and dark J−V curves intersect. We model the J−V characteristics with a main diode formed between the n-type ZnO nanocrystal (NC) layer and p-type PbS QD layer in series with a leaky Schottky-diode formed between PbS QD layer and metal contact. We show how the characteristics of the two diodes depend on QD size, metal work function, and PbS QD layer thickness, and we discuss how the presence of the back diode complicates finding an optimal layer thickness. Finally, we present Kelvin probe measurements to determine the Fermi level of the QD layers and discuss band alignment, Fermi-level pinning, a...

Reverse current-voltage characteristics of metal-silicide Schottky diodes

Abstract: The soft behavior of reverse biased Schottky barrier diodes has often been difficult to interpret quantitatively. The development of metal-silicide devices with diffused guard rings has made it possible to verify experimentally an advanced theoretical model. Reverse characteristics can now be accurately predicted over wide ranges of current, voltage, barrier height and temperature. The theoretical description accounts for anisotropy of effective masses, scattering by optical phonons, and quantum mechanical reflection and tunneling at the metal-semiconductor interface. These considerations yield practical Richardson constants equal to 112 for electrons and 32 for holes in silicon. Absence of true saturation in the reverse characteristic is caused by an electric field dependence of the effective barrier height. In addition to the usual image-force correction, the barrier height is lowered by a newly recognized effect attributed to an electrostatic dipole layer at the metal-semiconductor interface. Experimental devices have been fabricated using RhSi, ZrSi2, and PtSi contacts, forming barriers in both n- and p-type silicon. The resulting structures have been found to be extremely stable and uniform; furthermore, the metal-semiconductor interface, produced by solid-solid chemical reaction, is believed to be free from intervening layers of oxide and other contaminants. When necessary to eliminate field-enhancement at the electrode periphery, diffused guard rings have been incorporated into the structures. Agreement between experimental data and theory is obtained over nearly five orders of magnitude in reverse bias and eleven orders of magnitude in reverse current density, usually with an rms deviation of less than 10 per cent.

Photoconductivity of Ultrathin Zinc Oxide Films

Abstract: Electrical and photoelectrical properties of nondoped and doped zinc oxide films coated on glass plates by the dip-coating method are investigated at room temperature in various ambient atmospheres. The dark conductivity of the nondoped films exponentially decreased with decreasing film thickness while the conductivity under illumination of 350 nm light was almost constant at 100 Scm-1 irrespective of the film thickness. Consequently thinner films showed larger photoresponse than thicker films. This thickness dependence is explained by the variation of ZnO particle size with the film thickness (fine particle model) and the additional effect of the Schottky barrier generated between the film and gold electrodes.

Formation of an electric dipole at metal-semiconductor interfaces

Abstract: The insensitivity of experimentally observed Schottky barrier height (SBH) to the metal work function, a phenomenon known as Fermi level pinning, has traditionally been attributed to the presence of interface states in the band gap of the semiconductor. A recent theory showed that the polarization of the chemical bonds at metal semiconductor interfaces could quantitatively account for the experimentally observed strength of Fermi level pinning on different semiconductors, without regard to the actual distribution of gap states. This bond polarization theory thus provides a coherent explanation of the Fermi level pinning effect, on the one hand, and the experimentally observed dependence of the SBH on interface structure, on the other hand. The method used in this theory, the electrochemical potential equalization method hitherto employed only in molecular physics, and its limitations are here discussed in detail, especially in the context of application to solid interfaces. Similarities and differences between this theory and the metal induced gap state theory are also discussed.