Optical analysis of photoemission
Photoemission optical analysis from thin films with uniaxial anisotropy, discussing reflectance, transmittance and divergence of Poynting vector
Pepper, S. V.↗
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The electronic states and electron-lattice interaction in the silver halides - Photoemission studies
Examining photoemission from silver halides from room to liquid nitrogen temperatures to determine electron energy states
Bauer, R. S.↗
Giant temperature dependence of photoemission from the silver halides
Anomalous temperature dependent silver halides photoemission related to lattice vibrationally dependent hybridization of valence states
Bauer, R. S.↗
Exciton-induced photoemission from KCl films
KCl films exciton-induced photoemission, discussing mechanism of photoelectron emission rise with time under steady UV radiation
Pong, W.↗
Photoemissive coating
Polystyrene coating is applied to holographic storage tube substrate via glow discharge polymerization in an inert environment. After deposition of styrene coating, antimony and then cesium are added to produce photoemissive layer. Technique is utilized in preparing perfectly organized polymeric films useful as single-crystal membranes.
Gange, R. A.↗
Photoemission from cesium-oxide-activated InGaAsP.
Zinc-doped InGaAsP quaternary III-V material of the proper composition range shows superior photoemission properties to either InGaAs or InAsP ternary material. The minority-carrier diffusion length in the quaternary material is at least as long as that in InAsP and much longer than observed in InGaAs. The barrier height at the InGaAsP-Cs2O interface is lowered by cooling, giving increased electron escape probability and new highs in quantum efficiency over a wide wavelength range. For example, a 1.06-micron quantum efficiency of 7.5%/incident photon was observed at -90 C.
James, L. W.↗
Photoemission from CsI - Calculation.
Calculations of optical and photoemission spectra for CsI based on first-order allowed transitions between Bloch-wave states are discussed. The calculations, utilizing energy-band data for CsI published by Onodera (1968), were performed by computer sampling of regions in the Brillouin zone. The photoelectric spectra of CsI, calculated on the basis of an interpolated band scheme, display features which are in general agreement with the experimentally determined photoelectric energy distribution curves.
Distefano, T. H.↗
Optical communication with two-photon coherent states. II - Photoemissive detection and structured receiver performance
In a previous paper (1978), the authors developed a method of analyzing the performance of two-photon coherent state (TCS) systems for free-space optical communications. General theorems permitting application of classical point process results to detection and estimation of signals in arbitrary quantum states were derived. The present paper examines the general problem of photoemissive detection statistics. On the basis of the photocounting theory of Kelley and Kleiner (1964) it is shown that for arbitrary pure state illumination, the resulting photocurrent is in general a self-exciting point process. The photocount statistics for first-order coherent fields reduce to those of a special class of Markov birth processes, which the authors term single-mode birth processes. These general results are applied to the structure of TCS radiation, and it is shown that the use of TCS radiation with direct or heterodyne detection results in minimal performance increments over comparable coherent-state systems. However, significant performance advantages are offered by use of TCS radiation with homodyne detection. The abstract quantum descriptions of homodyne and heterodyne detection are derived and a synthesis procedure for obtaining quantum measurements described by arbitrary TCS is given.
Shapiro, J. H.↗
Internal photoemission in Ag-Al2O3-Al junctions
The magnitude of the photon-induced current in Ag-Al2O3-Al metal-oxide-metal junctions has been studied as a function of photon energy and angle of incident radiation. Photocurrents were theoretically analyzed on the basis of a modified vacuum photoemission model (Jain, 1975; Slayman et al., to be published). Optical constants previously reported in the literature (Irani et al., 1971; Ehnrereich et al., 1963) were used to calculate the true spatial generation rate in Ag and Al as a function of the angle, polarization of incident radiation, and film thickness. Results were found to be in very good agreement with experimentally determined values for a tunable dye laser with a KDP doubling crystal pumped by a Q-switched Nd:YAG laser with a LiIO3 doubling crystal. The system provided risetimes of 50 ns or less and peak powers of 10 W. Under short circuit conditions, the photoresponse to incident power was linear up to available power densities of 10 kW/sq cm. Quantum efficiencies of about 0.1% at zero-bias, near 3.8 eV under P polarization, were typically observed.
Guedes, J. M. P.↗
Optical communication with two-photon coherent states. III - Quantum measurements realizable with photoemissive detectors
Homodyne detection is shown to achieve the same signal-to-noise ratio as the quantum field quadrature measurement, thus providing a receiver which realizes linear modulation TCS performance gain. The full equivalence of homodyne detection and single-quadrature field measurement is established. A heterodyne configuration which uses a TCS image-band oscillator in addition to the usual coherent state local oscillator is studied. Results are obtained by means of a representation theorem which shows that photoemissive detection realizes the photon flux density measurement.
Yuen, H. P.↗
Photoemission measurements of interface barrier energies for tunnel oxides on silicon
Internal photoemission measurements of the Si/SiO2 and Al/SiO2 barrier heights on oxides of tunneling thickness (43-56 A) are compared with measurements on thick oxides (310 A and greater) and the barrier heights are found to be the same. The results suggest that substantially thinner oxides, grown by the same method, can be characterized by the same barrier heights. Limits to the experimental technique posed by photovoltaic and displacement currents, and transport of hot carriers in the tunnel oxide are discussed.
Dressendorfer, P. V.↗
The development of photoemission spectroscopy and its application to the study of semiconductor interfaces Observations on the interplay between basic and applied research (Welch Memorial Lecture)
A sketch is given of the development of photoemission electron spectroscopy (PES) with emphasis on the author's own experience. Emphasis is placed: (1) on the period between 1958-1970; (2) on the various developments which were required for PES to emerge; and (3) on the strong interactions between applied/fundamental and knowledge/empirically based research. A more detailed discussion is given of the recent (1975-present) application of PES to study the interfaces of III-V semiconductors.
Spicer, W. E.↗
Soft X-ray photoemission with the SSX-100 spectrometer
Photoemission and SEXAFS experiments were conducted using a double crystal monochromator at the Stanford Synchrotron Radiation Laboratory. Photoelectrons were detected using a Surface Science Laboratories SSX-100 electron analyzer, which employs a magnetic/electrostatic lens, hemispherical geometry, and a two-dimensional position-sensitive detector. In the kinetic energy range of interest (1000-2000 eV), a significant improvement in count rate was observed over a single channel cylindrical mirror analyzer system. Ten second scans of the KLL silicon Auger peak manifold were recorded at a large number of photon energies for subsequent determination of SEXAFS spectra.
Hecht, M. H.↗
Photoemission studies of core level shifts in HgCdTe, CdMnTe, and HgZnTe
The results of photoemission studies of core level shifts in the Hg(1-x)Cd(x)Te, Cd(1-x)Mn(x)Te, and Hg(1-x)Zn(x)Te alloys are discussed. In Hg(0.7)Cd(0.3)Te, the Hg 5d level is found to shift to lower binding energy by 0.1 eV, and the Cd 4d level to shift to higher binding energy by 0.25 eV upon alloying (relative to their binaries). The Born-Haber cycle is used to determine core level binding energies relative to the valence-band maximum in the context of tight-binding theory, and calculated core level shifts upon alloying in HgCdTe are shown to be too small to account for the observed values. A natural valence-band offset between HgTe and CdTe of 0.35 eV is found.
Shih, C. K.↗
Infrared response from metallic particles embedded in a single-crystal Si matrix - The layered internal photoemission sensor
Infrared radiation at wavelengths of 1-2 microns has been detected in a new device labeled the layered internal photoemission sensor. The device structure, which is grown by molecular beam epitaxy, incorporates epitaxial CoSi2 particles with dimensions of 10-50 nm. Radiation absorbed by these particles photoexcites carriers into a surrounding single-crystal silicon matrix. A peak quantum efficiency of 1.3 percent is measured, which is approximately six times higher than in planar CoSi2 Schottky diodes with 5-nm silicide thickness.
Fathauer, R. W.↗
Novel Si(1-x)Ge(x)/Si heterojunction internal photoemission long-wavelength infrared detectors
The feasibility of a novel p(+)-Si(1-x)Ge(x)-p-Si heterojunction internal photoemission (HIP) IR detector is demonstrated. A degenerately doped p(x)-Si(1-x)Ge(x) layer is required for strong IR absorption to generate photoexcited holes. The Si(1-x)Ge(x) layers are grown by molecular beam epitaxy, with boron concentrations up to 10 to the 20th/cu cm achieved by using an HBO2 source. Photoresponse at wavelengths ranging from 2 to 10 microns has been obtained with quantum efficiencies above 1 percent. The tailorable cutoff wavelength of the HIP detector has been demonstrated by varying the Ge composition ratio in the Si(1-x)Ge(x) layers.
Lin, T. L.↗
Heterojunction-Internal-Photoemission Infrared Detectors
New type of photodetector adds options for design of imaging devices. Heterojunction-internal-photoemission (HIP) infrared photodetectors proposed for incorporation into planar arrays in imaging devices required to function well at wavelengths from 8 to 17 micrometers and at temperatures above 65 K. Photoexcited electrons cross energy barrier at heterojunction and swept toward collection layer. Array of such detectors made by etching mesa structures. HIP layers stacked to increase quantum efficiency. Also built into integrated circuits including silicon multiplexer/readout circuits.
Maserjian, Joseph↗
Photovoltaic effects in photoemission studies of Schottky barrier formation
It is shown here that much of the recent photoelectron spectroscopy literature describing the onset of pinning in adsorbate-semiconductor systems at low temperature must be reinterpreted in light of surface photovoltaic effects. Two sources of surface charging are discussed, both of which are strongly enhanced at low temperature. The surface photovoltage resulting from separation of electron-hole pairs by the electric field in the depletion region is usually the dominant source of surface potential shifts, and causes flattening of the semiconductor bands. In addition, surface charging due to photoemission into the vacuum may reverse bias a p-type diode at low temperatures, causing increase band bending.
Hecht, M. H.↗