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.

Reversed bias Pt/nanostructured ZnO Schottky diode with enhanced electric field for hydrogen sensing

Abstract: In this paper, the effect of electric field enhancement on Pt/nanostructured ZnO Schottky diode based hydrogen sensors under reverse bias condition has been investigated. Current–voltage characteristics of these diodes have been studied at temperatures from 25 to 620 °C and their free carrier density concentration was estimated by exposing the sensors to hydrogen gas. The experimental results show a significantly lower breakdown voltage in reversed bias current–voltage characteristics than the conventional Schottky diodes and also greater lateral voltage shift in reverse bias operation than the forward bias. This can be ascribed to the increased localized electric fields emanating from the sharp edges and corners of the nanostructured morphologies. At 620 °C, voltage shifts of 114 and 325 mV for 0.06% and 1% hydrogen have been recorded from dynamic response under the reverse bias condition.

/sup 60/Co gamma irradiation effects on n-GaN Schottky diodes

Abstract: The effect of /spl gamma/-ray exposure on the electrical characteristics of nickel/n-GaN Schottky barrier diodes has been investigated using current-voltage (I-V), capacitance-voltage (C-V), and deep-level transient spectroscopy (DLTS) measurements. The results indicate that /spl gamma/-irradiation induces an increase in the effective Schottky barrier height extracted from C-V measurements. Increasing radiation dose was found to degrade the reverse leakage current, whereas its effect on the forward I-V characteristics was negligible. Low temperature (/spl les/50) post-irradiation annealing after a cumulative irradiation dose of 21 Mrad(Si) was found to restore the reverse I-V characteristics to pre-irradiation levels without significantly affecting the radiation-induced changes in C-V and forward I-V characteristics. Three shallow radiation-induced defect centers with thermal activation energies of 88 104 and 144 meV were detected by DLTS with a combined production rate of 2.12 /spl times/ 10/sup -3/ cm/sup -1/. These centers are likely to be related to nitrogen-vacancies. The effect of high-energy radiation exposure on device characteristics is discussed taking into account possible contact inhomogeneities arising from dislocations and interfacial defects. The DLTS results indicate that GaN has an intrinsically low susceptibility to radiation-induced material degradation, yet the effects observed in the Schottky diode I-V and C-V characteristics indicate that the total-dose radiation hardness of GaN devices may be limited by susceptibility of the metal-GaN interface to radiation-induced damage.

Schottky barrier inhomogeneities at the interface of few layer epitaxial graphene and silicon carbide

Abstract: In this work, we study electron transport across the heterojunction interface of epitaxial few-layer graphene grown on silicon carbide and the underlying substrate. The observed Schottky barrier is characterized using current-voltage, capacitance-voltage and photocurrent spectroscopy techniques. It is found that the graphene/SiC heterojunction cannot be characterized by a single unique barrier height because of lateral barrier inhomogeneities. A Gaussian distribution of barrier heights with a mean barrier height φBm=1.06eV and standard deviation σ=137±11meV explains the experimental data quite well.

Metal contacts to silicon and indium‐phosphide‐cleaved surfaces and the influence of intermediate adsorbed layers

Abstract: Detailed studies, using a range of experimental techniques, are described of the interfaces formed between metals and the semiconductors silicon and indium phosphide. For contacts between Ag or Au and cleaved (111) Si the existence of thin adlayers of oxygen or chlorine at the interface makes little difference to the magnitude of the Schottky barrier formed, although the adlayers totally change the electronic structure of the free surface. Au, Ag, and Cu contacts on clean (110) surfaces of InP yield good Schottky barriers but exposure of the clean surface to oxygen, air or chlorine prior to deposition of the metal electrodes leads to low apparent barrier contacts at room temperature. Reactive metals such as Al, Fe, and Ni also yield low barrier contacts, at room temperature, when deposited on clean surfaces of InP. These results coupled with studies on other materials cast some doubt about the usefulness of the quantity S, ’’the index of interface behavior’’ often used to describe metal–semiconductor interfaces and on the existence of the much quoted covalent‐ionic transition. The present results on InP may be understood in terms of a defect model and details of this model are discussed. The interface electronic properties are dominated by chemical and metallurgical effects.

Reduced contact resistance between an individual single-walled carbon nanotube and a metal electrode by a local point annealing

Abstract: The achievement of low-resistance contact is a key requirement for carbon-electrode electronics. In this study, we have obtained contacts with very low resistance between an individual single-walled carbon nanotube (SWNT) and palladium (Pd) electrodes using electric-current-induced Joule heating without destroying the field effect transistor device that these form. The SWNT is deposited onto Pd electrodes prepatterned on a SiO2/Si substrate, through which an electrical pulse is applied for a microsecond duration. As a result, the source?drain current through the SWNT is greatly increased owing to the elimination of tunnelling barriers between the SWNT and the electrodes. In the case of semiconducting SWNTs, the Schottky barrier is estimated to increase slightly after pulse annealing in some cases, resulting in a relatively high resistance and asymmetrical current?voltage characteristics.