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Showing papers on "Schottky barrier published in 1986"


Journal ArticleDOI
TL;DR: In this paper, the difference in apparent barrier height as obtained from capacitancevoltage and current-voltage measurements on Al/p-InP Schottky barriers was explained by introducing a distribution of barrier heights over the contact area and a temperature dependence of the real barrier height.
Abstract: The difference in apparent barrier height as obtained from capacitance-voltage and current-voltage measurements on Al/p-InP Schottky barriers was explained by introducing a distribution of barrier heights over the contact area and a temperature dependence of the real barrier height. Taking into account this barrier height distribution and the temperature dependence of the barrier height, we were also able to explain the measured values of the effective Richardson constant. As a result a modified expression for the temperature dependence of the current-voltage characteristics was obtained.

521 citations


Journal ArticleDOI
TL;DR: In this article, a field effect transistor (FET) using a two-dimensional electron gas (2DEG) as an electron channel is fabricated from GaAs grown by molecular-beam epitaxy.
Abstract: A field-effect transistor (FET) using a two-dimensional electron gas (2DEG) as an electron channel is fabricated from GaAs grown by molecular-beam epitaxy. The doping profile of the field-effect transistor is described by the Dirac delta (δ) function. The subband structure of δ-doped GaAs is calculated. The characteristics of the δFET are a high concentration of the 2DEG, a high breakdown voltage of the Schottky contact, a narrow distance of the 2DEG from the gate, and a high transconductance. These properties are analyzed. Preliminary results for the extrinsic transconductance and for the transit frequency are obtained from δFET's having nonoptimized structures.

186 citations


Journal ArticleDOI
M. Ito1, Osamu Wada1
TL;DR: In this paper, a metal-semiconductor-metal (MSM) photodiodes using the same undoped GaAs layer that is used as a buffer layer in the epitaxial structure for GaAs field effect transistors (FET's) are presented.
Abstract: We present the fabrication and characterization of metal-semiconductor-metal (MSM) photodiodes using the same undoped GaAs layer that is used as a buffer layer in the epitaxial structure for GaAs field effect transistors (FET's). To study the dark current mechanism, various metal electrodes used for Schottky contacts are examined. A drastic V-shape relationship between the dark current of MSM photodiode and the Schottky barrier height is found. An extremely low dark current (a few nanoamperes) in the MSM photodiode is obtained by using tungsten silicide as electrode metal. It is concluded that the dark current is a function of a rivalry relation between the electron injection at the cathode and the hole injection at the anode. The internal gain of the MSM photodiode with tungsten silicide contacts is found, and possible mechanisms are discussed. A flat frequency response up to 1.3 GHz is obtained. The results shows the feasibility of MSM photodiodes for use as photodetectors with low minimum detectable power, and their applicability to monolithic integration with FET circuits.

174 citations


Journal ArticleDOI
01 Jun 1986
TL;DR: In this article, the authors provide the very best offer by getting the amazing book metal semiconductor schottky barrier junctions and their applications in this web site, which can be used to locate hundreds sort of e-books.
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133 citations


Journal ArticleDOI
TL;DR: In this article, the electrical properties of a large number of metal/n-type GaAs (Cr, Mn, Sn, Ni, Al, Pd, Cu, Ag, Au) diodes were investigated.
Abstract: We report here a systematic study of the electrical properties of a large number of metal/n-type GaAs (Cr, Mn, Sn, Ni, Al, Pd, Cu, Ag, Au) diodes. Diodes were fabricated on cleaved GaAs(110) surfaces under ultrahigh-vacuum conditions with in situ metal deposition. Using current-voltage (I-V) and capacitance-voltage (C-V) measuring techniques, we were able to obtain very reliable and consistent determinations of the barrier height ${\ensuremath{\varphi}}_{b}$ and ideality factor n. All of the metal-semiconductor systems formed on lightly doped (5\ifmmode\times\else\texttimes\fi{}${10}^{16}$/${\mathrm{cm}}^{3}$) n-type GaAs substrates were characterized by near-unity (1.05) ideality factors. A decrease in the effective I-V barrier height, an increase in the ideality factor in forward bias and a strong voltage dependence on the thermionic emission currents in reverse bias were found for diodes formed on the more heavily doped samples.These changes are essentially metal independent, but depend strongly on the doping of the substrate. The characterization (and elimination in some cases) of peripheral leakage currents from the thermionic emission current is found to be essential in obtaining consistent results in our work and in reinterpreting some of the prior work in the literature. The dominant leakage current flows through a small area, low barrier at the periphery of the device and can be eliminated by mesa etching. The consistent and reproducible barrier-height determinations reported in this study, when combined with the results of recent surface-sensitive studies, are a particularly critical test of models of Schottky-barrier formation.The barrier heights measured from the electrical characteristics of thick-metal-film diodes were found to be essentially identical to those reported during the initial stages (submonolayer to several monolayers of metal) of Schottky-barrier formation by photoemission spectroscopy. This agreement indicates that the physical mechanism responsible for Fermi-level pinning in the thick-metal Schottky diodes is first established at submonolayer to several-monolayer coverages of adatoms and an atomic scale model is therefore necessary to account for the available experimental data. No strong correlation between the barrier heights and the work function of the metal or chemistry at the interface was found. Also, diodes formed on clean GaAs(110) surfaces were found to have essentially identical barrier heights to those formed on clean GaAs(100) surfaces and on contaminated (i.e., chemically prepared) GaAs(100) and GaAs(110) surfaces. Several currently popular models concerned with the physical mechanism responsible for the formation of the Schottky barrier are discussed, and the unified defect model is found to be most consistent with the experimental data.

128 citations


Journal ArticleDOI
TL;DR: A new characterization method is presented for traps at the interfacial layer of Schottky contacts based on ac-admittance measurements and a new trap transistor model which quantitatively explains the measured ac behavior as well as the dc characteristics.
Abstract: We present a new characterization method for traps at the interfacial layer of Schottky contacts. This method is based on ac-admittance measurements and a new trap transistor model which quantitatively explains the measured ac behavior as well as the dc characteristics. In particular we propose the ac current across the interface to consist of capacitive as well as of conductive parts. We apply the analysis to Au/GaAs Schottky contacts and find a weak energy dependence for the density of interface states in the band gap of GaAs.

111 citations


Journal ArticleDOI
TL;DR: Ultraviolet-sensitive photodiodes have been made using the Schottky barrier formed in the contact layer between a thin sputtered layer of ZnO and Au by optimizing the sputtering parameters and the IV characteristics and the sensitivity spectra were investigated.
Abstract: Ultraviolet-sensitive photodiodes have been made using the Schottky barrier formed in the contact layer between a thin sputtered layer of ZnO and Au. The sputtering parameters for the ZnO layer were optimized. The IV characteristics and the sensitivity spectra of the ZnO–Au photodiodes were investigated.

98 citations


Journal ArticleDOI
Jerry Tersoff1
TL;DR: In this article, a model of Schottky barrier formation based on intrinsic interface or surface states suggests Fermi-level pinning at or near some effective mid-gap energy, which can be calculated directly from the bulk semiconductor band structure.

98 citations


Journal ArticleDOI
Ernst Bucher, S. Schulz, M.Ch. Lux-Steiner, P. Munz, U. Gubler, F. Greuter1 
TL;DR: The work function of 13 polycrystalline transition metal silicides was measured by photo-emission in this article, and their values were discussed in relationship to their Schottky barrier heights on n-Si.
Abstract: The work function of 13 polycrystalline transition metal silicides was measured by photoemission in uhv. Their values are discussed in relationship to their Schottky barrier heights on n-Si. While there appears to be a weak correlation for a certain group of transition metal silicides, the values of the 5d-noble metal silicides including some of the lattice matched Ni silicides appear to be completely uncorrelated. Experimental values of work functions are compared to the values proposed previously by Freeouf.

96 citations


Journal ArticleDOI
TL;DR: In this article, the authors compared the results of surface sensitive photoemission spectroscopy performed during the initial stages of Schottky barrier formation (sub to several monolayer coverages of metals, as well as nonmetals) to the results from device electrical measurements for thick metal coverages (∼1000 A) to investigate the physical mechanisms involved in Fermi level pinning on III-V semiconductor surfaces.
Abstract: We present the results of a systematic study designed to investigate the physical mechanisms involved in Fermi level pinning on III–V semiconductor surfaces. This study compares the results of surface sensitive photoemission spectroscopy performed during the initial stages of Schottky barrier formation (sub to several monolayer coverages of metals, as well as nonmetals) to the results of device electrical measurements for thick metal coverages (∼1000 A). These results give strong support for the basic premises of the unified defect model (UDM), as first proposed in 1979. However, several revisions were found to be important in correcting and/or sharpening several details of the UDM. As proposed in 1979, we find that the same native defect energy levels are created independent of the foreign atoms deposited on the clean GaAs surface. However, the small but finite range in pinning positions in GaAs and InP and the correlation that high (low) barrier heights are formed for high (low) electronegativity metals on n‐type substrates indicates that electronic interactions between the foreign atoms and the GaAs can determine the charge state of the defects which are found to pin the Fermi level. The donor at 0.1 eV from the conduction band minimum (CBM) originally associated with a native defect of InP in 1979, was shown to be due to a level in the oxide on the surface of the InP. The reassignment of the energy levels of the native defects in InP to an acceptor level at CBM‐0.3 eV and a donor level at CBM‐0.5 eV was found to be more consistent with the available experimental data.

94 citations


Journal ArticleDOI
01 Jun 1986-Nature
TL;DR: In this paper, a new heterogeneous poly crystalline n-CuInS2 based semiconductor which has yielded conversion efficiencies of 9.7% in an electrochemical cell was reported.
Abstract: The high absorptivity associated with a direct energy gap in the optimum range for solar-energy conversion makes CuInS2 a particularly promising material for efficient solar-energy conversion1. Achieved solar-to-electrical conversion efficiencies have been limited to ∼6% (refs 2–8). We report here a new heterogeneous poly crystalline n-CuInS2 based semiconductor which has yielded conversion efficiencies of 9.7% in an electrochemical cell. The high photoactivity is also evident in a Schottky barrier solar cell configuration. The origin of the improved efficiency is attributed to impurity scavenging by In spheres resulting from a modified vapour/liquid/solid (VLS) growth process9–11 and the influence of the acidic iodine iodide electrolyte on the cell performances.

Journal ArticleDOI
M. O. Aboelfotoh1, King-Ning Tu1
TL;DR: The n-type and p-type barrier heights for both the metal and the reacted silicide phase were found to decrease with increasing temperature and with the same coefficient within the experimental accuracy, consistent with the predictions of recent models of barrier formation based on Fermi-level pinning in the center of the indirect band gap.
Abstract: The Schottky-barrier heights of Ti and ${\mathrm{TiSi}}_{2}$ on both n-type and p-type Si(100) have been measured in the temperature range 175--295 K with use of a current-voltage technique. Auger-electron spectroscopy, Rutherford backscattering spectroscopy, and glancing-angle x-ray diffraction were used to monitor the silicide-formation reaction. The results showed that silicide formation has only a small effect on barrier height. The n-type and p-type barrier heights for both the metal and the reacted silicide phase were found to decrease with increasing temperature and with the same coefficient within the experimental accuracy. This coefficient was found to be approximately equal to one-half the temperature coefficient of the indirect energy gap in Si. These results are consistent with the predictions of recent models of barrier formation based on Fermi-level pinning in the center of the indirect band gap.

Journal ArticleDOI
TL;DR: In this article, a method for obtaining thin films of doped molecular materials in a complete absence of oxygen is described, which consists in simultaneously subliming under vacuum the electroactive compound (a metallophthalocyanine) and the electron acceptor or electron donor doping agent.
Abstract: A new method for obtaining thin films of doped molecular materials in a complete absence of oxygen is described. It consists in simultaneously subliming under vacuum the electroactive compound—a metallophthalocyanine—and the electron acceptor or electron donor doping agent. The extent of doping is controlled by the relative rates of sublimation. The ac and dc electrical properties of thin films are determined under high vacuum as to eliminate the influence of oxygen which has been previously shown to be of the utmost importance. Both p‐ and n‐type dopings have been achieved; the increase of conductivity reaches six orders of magnitude for p‐type doping with dichlorodicyanoquinone (DDQ). For the first time a rectifying contact between doped phthalocyanine thin films and aluminum has been observed in strict absence of oxygen.


Journal ArticleDOI
TL;DR: In this article, a new method for measuring the density of states at semiconductor surfaces using organic-on-inorganic (OI) contact barriers is suggested, which is an extension of previous models of OI diode behavior which includes the ac admittance characteristics, and which considers the range of validity of approximations to OI capacitance used in previous experiments.
Abstract: A new method for measuring the density of states at semiconductor surfaces using organic‐on‐inorganic (OI) semiconductor contact barriers is suggested. This work is an extension of previous models of OI diode behavior which includes the ac admittance characteristics, and which considers the range of validity of approximations to OI diode capacitance used in previous experiments. The theory describes the potential distribution across the device. We consider the case of ideal OI diodes, as well as diodes with significant densities of states at the inorganic semiconductor surface. This analysis leads to a technique whereby the low‐frequency conductance and capacitance characteristics can be used to obtain information about the magnitude and the energy distribution of surface states in the inorganic semiconductor bandgap. Also, the carrier concentration profiles of the substrate can be conveniently obtained. Due to the noninvasive nature of the organic/inorganic contact, information about the density of states at relatively undisturbed semiconductor surfaces obtained via this technique may prove useful in determining the processes involved in Schottky barrier formation and metal‐insulator‐semiconductor diode surface properties. This theory has been applied to the investigation of surfaces of III‐V alloy semiconductor‐based OI diodes, and the experimental results will be presented in a subsequent paper. In addition, an expression for the OI diode n value obtained from the forward current‐voltage characteristics is derived. It is found that the n value depends on surface states which are in equilibrium with the organic as well as the inorganic materials. Estimates of the surface state densities obtained from previously reported n values are consistent with expectations for the semiconductors under test.

Journal ArticleDOI
TL;DR: Extensive finite-element analyses on MMIC slow-wave structures with both Iocalized and layered models are presented in this article, and good agreement is achieved between the data presented here and other theoretical results and experiments Higher order elements that improve accuracy are discussed.
Abstract: Extensive finite-element analyses on MMIC slow-wave structures with both Iocalized and layered models are presented Good agreement is achieved between the data presented here and other theoretical results and experiments Higher order elements that improve accuracy are discussed The comparative studies for Schottky contact microstrip and coplanar waveguide with Iocalized and layered models are presented Potential applications of the Iocalized models to more general and practical slow-wave circuits are also discussed

Journal ArticleDOI
TL;DR: In this paper, the effect of annealing on the electrical characteristics of epitaxial aluminum/gallium arsenide Schottky barriers prepared by molecular beam epitaxy has been studied and compared with the behavior of polycrystalline aluminum contacts deposited in a conventional evaporation system.
Abstract: The effect of annealing on the electrical characteristics of epitaxial aluminum/gallium arsenide Schottky barriers prepared by molecular‐beam epitaxy has been studied and compared with the annealing behavior of polycrystalline aluminum contacts deposited in a conventional evaporation system. It was found that the epitaxial contacts showed remarkably stable electrical characteristics, the forward characteristics remaining exponential over 6 decades of current after annealing for 1 h at 500 °C, with a slight degradation of n value from 1.01 to 1.02 and a very small recombination component. In the reverse direction, the characteristics improved on annealing, with a reduction in current from 9×10−10 to 6×10−11 A at a reverse bias of 1 V. In contrast, the polycrystalline contacts showed a pronounced recombination component after annealing, with an increase in n to between 1.05 and 1.09, and a significant degradation in reverse characteristics. Auger depth profiling showed that the epitaxial contacts exhibited ...

Proceedings Article
01 Jan 1986
TL;DR: In this paper, a comparison of Schottky contact microstrip and coplanar waveguide with both Iocalized and layered models is presented, and potential applications of the Iocalised models to more general and practical slow-wave circuits are also discussed.
Abstract: Extensive finite-element analyses on MMIC slow-wave structures with both Iocalized and layered models are presented. Good agreement is achieved between the data presented here and other theoretical results and experiments. Higher order elements that improve accuracy are discussed. The comparative studies for Schottky contact microstrip and coplanar waveguide with Iocalized and layered models are presented. Potential applications of the Iocalized models to more general and practical slow-wave circuits are also discussed.

Journal ArticleDOI
TL;DR: By including the effects of electron-hole recombination and electron trapping in the analysis of the transport properties of Schottky diodes, it is possible to obtain a more accurate estimate of the barrier height as discussed by the authors.
Abstract: By including the effects of electron-hole recombination and electron trapping in the analysis of the transport properties of Schottky diodes it is possible to obtain a more accurate estimate of the Schottky-barrier height. The magnitude of the barrier height obtained from an analysis of the forward I-V characteristics of CdTe Schottky diodes is in better agreement with that obtained from C-V measurements than that obtained by using the conventional procedure of introducing an ideality factor into the 'ideal diode' equation.

Journal ArticleDOI
TL;DR: In this article, caracterisation de polyheterocycliques et polyaromatiques conducteurs, mecanisme de conduction electrique dans les polyheterocytecliques and polyaramatiques dopes, copolymeres conducteur, batteries, cellule photoelectrochimique, barrieres de Schottky, cellules solaires et dispositifs a l'etat solide, capteurs and usages medicaux, applications diverses

Journal ArticleDOI
TL;DR: In this article, the surface barrier heights φbn and room temperature band gaps of Si−doped InxAl1−xAs layers grown by molecular beam epitaxy on n-type (100) oriented InP substrates have been determined as a function of composition with capacitance versus voltage, internal photoemission, photoluminescence, and double-crystal x-ray rocking curve measurements for 0.45 0.78, n−type surfaces might accumulate and p-type surfaces are likely to be inverted.
Abstract: The surface barrier heights φbn and room‐temperature band gaps Eg of Si‐doped InxAl1−xAs layers grown by molecular beam epitaxy on n‐type (100) oriented InP substrates have been determined as a function of composition with capacitance versus voltage, internal photoemission, photoluminescence, and double‐crystal x‐ray rocking curve measurements for 0.45 0.78, n‐type surfaces might be accumulated and p‐type surfaces are likely to be inverted.

Journal ArticleDOI
TL;DR: In this paper, an extension of earlier work by van der Ziel on infrared detection in Schottky-barrier diodes has been presented, where the electrons participating in the charge-transport process across the barrier are subdivided into four groups based on their initial velocity.
Abstract: Room-temperature noise measurements at 2.2, 12, and 97.5 GHz were performed on commercial silicon Schottky-barrier diodes and are shown to agree with the model presented in this work. This model is an extension of earlier work by van der Ziel on infrared detection in Schottky-barrier diodes. In the theoretical analysis, the electrons participating in the charge-transport process across the barrier are subdivided into four groups based on their initial velocity. The contribution of each group to the device conductance, susceptance, and current spectral intensity was incorporated including the effects of the transit time. By taking each of these effects into account, an accurate model which applies over a wide range of bias and frequency has been developed. Although the emphasis of this model has been on the high-frequency performance, the model also gives the correct results in the low-frequency limit.

Journal ArticleDOI
TL;DR: Schottky-barrier field effect transistors have been successfully fabricated from 3C-type SiC epilayers by chemical vapor deposition in this paper, where Au and Al electrodes were used for Schottky barrier gate contacts and ohmic (source and drain) contacts for n−type SiCs.
Abstract: Schottky‐barrier field‐effect transistors have been fabricated first from 3C‐type SiC. Al‐doped p‐type and nondoped n‐type 3C‐SiC epilayers were successively grown on p‐type Si substrates by chemical vapor deposition. Au and Al electrodes were used for Schottky‐barrier gate contacts and ohmic (source and drain) contacts for n‐type SiC. Transistor operation was observed for the first time for the field‐effect transistors of 3C‐SiC.

Journal ArticleDOI
W. E. Spicer1, Tom Kendelewicz1, Nathan Newman1, Ken K. Chin1, I. Lindau1 
TL;DR: In this article, the most popular models for the III-V semiconductors are examined in terms of the metal:III-V chemistry including its correlation with barrier height and/or the effect of metal thickness.

Journal ArticleDOI
R. Ludeke1, G. Landgren1
TL;DR: Several refinements of the photoemission technique and data analysis are discussed and shown to be relevant to both the accurate determination of band bending and the chemical characterization of the interface.
Abstract: Photoemission experiments have shown that strong chemical reactions occur at clean Pd/GaAs(110) and Ti/GaAs(110) interfaces formed at room temperature in ultrahigh vacuum. In both cases elemental Ga was found dispersed in the metal film, which also had a metal-As compound segregated to its surface. In addition, what appears to be elemental As was observed on the Pd-covered surfaces. Subsurface reactions were identified well below monolayer (ML) coverages. The evolution of band bending with increasing metal coverage starting near 0.001 ML is strongly dependent on the metal and results in Schottky-barrier heights of 0.73 (0.70)\ifmmode\pm\else\textpm\fi{}0.05 eV for Ti and 1.01 (0.42)\ifmmode\pm\else\textpm\fi{}0.05 eV for Pd on n-type (p-type) GaAs(110). Strong emission from the transition-metal d orbitals in the band-gap region of the GaAs was observed for coverages \ensuremath{\gtrsim}0.01 ML and represents the first direct spectroscopic identification of occupied interface states responsible for Fermi-level pinning. The latter observation together with differing coverage dependences for the final pinning positions for Pd and Ti indicate a new mechanism for the formation of a Schottky barrier. It is suggested that rebonding between the transition metal and the GaAs at the interface produces partially occupied d orbitals which lie in the semiconductor band gap. In addition, several refinements of the photoemission technique and data analysis are discussed and shown to be relevant to both the accurate determination of band bending and the chemical characterization of the interface.

Journal ArticleDOI
Haruo Yamagishi1
TL;DR: In this article, an Au/n-InP Schottky contact formation on an InP surface exposed to plasma-induced oxygen radicals and its electrical characteristics have been investigated, showing an ideality factor n of about 1.06 and an enhanced barrier height B0 of about 0.7 eV, quite stable for annealing temperatures up to about 300°C.
Abstract: An Au/n-InP Schottky contact formation on an InP surface exposed to plasma-induced oxygen radicals and its electrical characteristics have been investigated. Auger electron spectroscopy (AES) measurements revealed the presence of oxygen atoms at the Au/InP interface, indicating an oxide-layer formation. The Schottky contacts showed an ideality factor n of about 1.06 and an enhanced barrier height B0 of about 0.7 eV, quite stable for annealing temperatures up to about 300°C. We observed a large decrease in the reverse leakage current, three orders of magnitude smaller than that of conventional Au/n-InP contacts. A barrier-height increase of about 0.2 eV could be interpreted on the bases of an inter-facial-layer model.

Journal ArticleDOI
TL;DR: In this article, the Schottky contact is used as a barrier for the tunneling curent between the subbands of the doping layer and the surface metal, and the energies of occupied and unoccupied levels are determined from distinct structures in the first derivative.

Journal ArticleDOI
TL;DR: In this article, reactively sputtered WNx films on a GaAs substrate have been investigated by electrical and physical analyses, and three types of sputtering systems: (1) magnetron sputtering system equipped with rf and dc mode; (2) sgun sputtering scheme, and (3) rf diode sputtering mechanism.
Abstract: Properties of reactively sputtered WNx films on a GaAs substrate have been investigated by electrical and physical analyses. WNx films were deposited from a pure W target by using three types of sputtering systems: (1) Magnetron sputtering system equipped with rf and dc mode; (2) S‐gun sputtering system; (3) rf diode sputtering system. The composition of WNx films was easily and reproducibly controlled by changing the N2 content in Ar–N2 mixed ambient gas. The WNx–GaAs system was both electrically and metallurgically stable even after high‐temperature annealing of up to 800 °C. The Schottky barrier height to n‐type GaAs was more than 0.8 V, which is the highest value obtained so far among any other refractory metals. Self‐aligned GaAs MESFET’s were successfully fabricated using a WNx gate. The transconductance was typically 150 mS/mm for 1.5 μm gate length.

Journal ArticleDOI
TL;DR: In this paper, a simple optical correlation technique was proposed to measure the intrinsic response speeds of fast photosensitive electronic devices, where neither high speed electrical connections to a device nor cross-correlation measurements between two devices are required.
Abstract: We report a simple optical correlation technique which is capable of measuring the intrinsic response speeds of fast photosensitive electronic devices. The appeal of the method is that neither high‐speed electrical connections to a device nor cross‐correlation measurements between two devices are required. An example is given of measurements of the response speed of a GaAs Schottky barrier photodiode. Under appropriate illumination conditions the detector is found to be sufficiently fast to be capable of replacing optical second harmonic generation techniques for monitoring the quality of a beam of 1.5 ps pulses.

Journal ArticleDOI
TL;DR: The first metal-semiconductor (MS) rectifying contact had been detected by Braun' as discussed by the authors, who reported that point contacts between a thin metal wire and a crystal showed a resistance dependent on the polarity of the applied voltage.
Abstract: More than 100 years ago, Braun' reported that the point contacts between a thin metal wire and a crystal showed a resistance dependent on the polarity of the applied voltage. The first metal-semiconductor (MS) rectifying contact had been detected. Since then, the MS interface has played an important role in many technological developments. However, a full understanding of the physics behind the barrier height has so far been elusive. and it remains a very active research field today.