Surface characterization of CdS0.62Se0.38 by X-ray photoelectron spectroscopy

Sputtering of compound semiconductor surfaces. II: Compositional changes and radiation-induced topography and damage

Abstract: Ion bombardment often leads to compositional changes in the surface layers of multicomponent targets. Such changes due to noble gas ion sputtering are discussed for InP and GaAs. The analyses show that the compositional change in InP (i.e., indium enrichment) is mainly due to preferential sputtering. In the case of GaAs. the changes are due to radiation-induced diffusion and segregation effects. Brief mention is made of compositional changes in a few other systems. The discussion on sputter-induced topography development deals mainly with InP because ion bombardment leads to dramatic topographical effects in this material. Ripple development on GaAs is also briefly discussed. Radiation damage has been well researched, and its mechanism and effects usually differ substantially when going from one semiconductor group to another. Bombardment-induced damage is briefly discussed for InP, GaAs, SiC, some II-VI semiconductors, and HgCdTe.

Photoelectric performance of TiO2 nanotube array photoelectrodes sensitized with CdS0.54Se0.46 quantum dots

Abstract: The photoelectrochemical performance of CdSSe quantum dots tethered to a framework of vertically oriented titania (TiO2) nanotubes was studied. The TiO2/CdSSe framework demonstrated improved charge transfer due to its unique band edge structure, thus validating the higher photocurrent generation. The composite film led to an 11-fold enhancement in comparison to the control TiO2 film, implying that the ternary quantum dots and the nanotubular structure of TiO2 work in tandem to promote charge separation and favorably impact photoelectrochemical performance. Further, the results also suggest that structural and optoelectronic properties of TiO2 films are significantly affected by the thicknesses of the CdSSe layer.

Structural and optical properties of CdS/PEO nanocomposite solid films

Abstract: In this paper solution mixing and casting of Cd(NO3)2·4H2O and poly(ethylene oxide) (PEO) at different molar ratios (1:100–1:600) followed by hydrogen sulfide treatment were employed to fabricate solid films of cadmium sulfide (CdS)/polyethylene oxide (PEO) nanocomposites. The nanocomposites were found to exhibit uniform distribution of CdS nanoparticles in the polymer matrix without any additional capping agent. Systematic investigations on the role of PEO on the optical properties of CdS are presented. The optical properties of the composites examined by UV–vis absorption spectroscopy show that the band gap of CdS nanoparticles increases from 2.45 eV to 2.54 eV with decreasing concentration of CdS in PEO films. X-ray diffraction pattern shows the broadening in shape of the PEO peaks which is induced by the CdS particles in PEO matrix. The CdS particle sizes ranging from 10 to 20 nm are clearly seen in a transmission electron microscope (TEM). The X-ray photoelectron spectroscopic studies (XPS) also confirm the presence of CdS in PEO. Fourier transform infrared spectroscopy studies using attenuated total reflectance (FTIR-ATR) indicate the influence of Cd2+ ion on C–O–C stretching in PEO and confirm the presence of CdS nanoparticles within PEO. Photoluminescence spectroscopy (PL) shows the broad emission due to the presence of surface trapped carrier states.

Photoelectrochemical properties of chemically deposited cadmium sulphoselenide (CdS1-xSex /ITO) thin films

Abstract: CdS1-xSex thin films were deposited by Chemical Solution onto ITO/glass substrates at 90 °C. Structural, optical and photoelectrochemical properties of the ternary solid solution films were evaluated in this work. The results revealed good crystalline quality of the CBD films as an effect of ITO substrate and deposition temperature. Additionally, the dense, flat and homogeneous morphology of the films transformed into clusters of plate-like structures as selenium content increased. Polycrystalline thin films with crystallite size varying from 17 to 6 nm as a function of x were obtained. Hexagonal nanocrystallites of CdS1-xSex films were revealed by TEM images. Band gap variation as a function of x was described by a polynomial equation with an optical bowing coefficient of 0.331. High energy emission of the radiative recombination process was observed from all films even without thermal treatment. The photoelectrochemical results indicated the n-type semiconductor nature of the films; flat band potential, carrier density and photocurrent decrease as Se is incorporated into the CdS lattice.

Colour tunable co-evaporated CdSxSe1-x (0 ≤ x ≤ 1) ternary chalcogenide thin films for photodetector applications

Abstract: Cadmium Sulfoselenide CdSxSe1-x (0 ≤ x ≤ 1) films were grown by thermal co-evaporation of source materials, CdS and CdSe, taken in the stoichiometric ratio. Systematic shift in the position of X-ray diffractogram (XRD) peak and optical absorption edge have confirmed the change in structural and optical properties as x varied from 0 to 1. Further, photoluminescence (PL) spectra revealed that ternary system has a minimum defect, which is the basic requirement for device applications. The Raman and X-ray photoelectron spectroscopy (XPS) studies have given concurrent results revealing the chemical states of the ternary samples. Detailed analysis of XPS has shown incorporation of oxygen in minor fraction, which proved to help in improving the photoresponse. Electrical study has shown that the electrical properties can varied by changing the composition. All the samples have exhibited n-type conductivity with carrier concentration in the range 1014 to 1015 cm−3. Finally, photoresponse study showed that sample with x = 0.2 is best suitable for photodetector, where the device can be operated over entire visible range.

Photoelectron and Auger Spectroscopy

Abstract: 1 Introduction.- 1. History.- 2. Scope of Present Book and Review of Past Books.- 3. Name-Calling.- 4. Areas Related to Electron Spectroscopy Not to be Discussed in Detail.- 4.1. Electron-Impact Spectroscopy.- 4.2. Photoemission.- 4.3. Penning Ionization Spectroscopy.- 4.4. Ion Neutralization Spectroscopy.- 5. Fields Related to Electron Spectroscopy.- 2 Instrumentation and Experimental Procedures.- 1. Source Volume.- 1.1. Excitation Devices.- 1.1.1. Electron Gun.- 1.1.2. X-Ray Tube.- 1.1.3. Synchrotron Radiation.- 1.1.4. Vacuum-UV Sources.- 1.2. Target Sample.- 1.2.1. Gases.- 1.2.2. Solids.- 1.2.3. Condensed Vapors, Liquids, and Targets at Other Than Room Temperature.- 1.3. Chamber for Angular Distribution Studies.- 1.4. Preacceleration and Deceleration.- 2. Analyzer.- 2.1. Cancellation of Magnetic Fields.- 2.1.1. Helmholtz Coils.- 2.1.2. Magnetic Shielding.- 2.2. Types of Analyzers.- 2.2.1. Retarding Grid.- 2.2.2. Dispersion.- 3. Detector Systems and Data Analysis.- 3.1. Single-Channel Detector.- 3.2. Position-Sensitive Detector.- 3.3. Scanning the Spectrum.- 3.4. Data Analysis.- 4. New Developments.- 5. Review of Commercial Instruments.- 5.1. AEI.- 5.2. Du Pont.- 5.3. Hewlett-Packard.- 5.4. McPherson.- 5.5. Perkin-Elmer.- 5.6. Physical Electronics.- 5.7. McCrone-RCI.- 5.8. Vacuum Generators, Inc..- 5.9. Varian.- 5.10. Others.- 3 Fundamental Concepts.- 1. Photoelectric Effect.- 2. Binding Energy.- 3. Final States and the Sudden Approximation.- 3.1. Spin-Orbit Splitting.- 3.2. Multiplet Splitting.- 3.3. Jahn-Teller Splitting.- 3.4. Electron Shakeoff and Shakeup.- 3.5. Configuration Interaction.- 3.6. Koopmans' Theorem and the Sudden Approximation.- 3.7. Vibrational and Rotational Final States.- 4. Atomic Wave Functions.- 5. Molecular Orbital Theory.- 5.1. Theoretical Models.- 5.1.1. Ab Initio Calculations.- 5.1.2. Semiempirical Calculations.- 5.2. Basis Set Extension and MO Mixing.- 5.3. Atomic and Molecular Orbital Nomenclature.- 5.3.1. Atoms.- 5.3.2. Molecules.- 4 Photoelectron Spectroscopy of the Outer Shells.- 1. Introduction.- 2. Energy Level Scheme.- 2.1. Binding Energy.- 2.2. Final States.- 2.2.1. Spin-Orbit Splitting.- 2.2.2. Multiplet Splitting due to Spin Coupling.- 2.2.3. Jahn-Teller Effect.- 2.2.4. Electron Shakeoff and Shakeup.- 2.2.5. Configuration Interaction.- 2.2.6. Resonance Absorption.- 2.2.7. Collision Peaks.- 3. Identification of the Orbital.- 3.1. Ionization Potentials.- 3.1.1. Characteristic Ionization Bands.- 3.1.2. Effects of Substituents.- 3.1.3. Sum Rule.- 3.1.4. The Perfluoro Effect.- 3.1.5. Dependence on Steric Effects.- 3.2. Identification of Orbitals by Vibrational Structure.- 3.3. Identification of Molecular Orbitals from Intensities of Ionization Bands.- 3.4. Identification of Molecular Orbitals by Angular Distribution.- 4. Comparison of PESOS with Other Experimental Data.- 4.1. Optical Spectroscopy.- 4.2. Mass Spectroscopy.- 5. Survey of the Literature on PESOS.- 5.1. Atoms.- 5.2. Diatomic Molecules.- 5.2.1. H2.- 5.2.2. N2 and CO.- 5.2.3. O2 and NO.- 5.2.4. Diatomic Molecules Containing Halogen.- 5.3. Triatomic Molecules.- 5.3.1. Linear Triatomic Molecules.- 5.3.2. Bent Triatomic Molecules.- 5.4. Organic Molecules.- 5.4.1. Methane, Alkanes, and Tetrahedral Symmetry.- 5.4.2. Unsaturated Aliphatics.- 5.4.3. Ring Compounds.- 5.4.4. Multiring Compounds.- 5.4.5. Organic Halides.- 5.4.6. Miscellaneous Organic Compounds Containing Oxygen, Nitrogen, Sulfur, and Phosphorus.- 5.5. Organometallics and Miscellaneous Inorganic Polyatomic Molecules.- 5.6. Ions, Transient Species, and Other Special Studies in PESOS.- 6. Studies on Solids.- 7. Analytical Applications of PESOS.- 5 Photoelectron Spectroscopy of the Inner Shells.- 1. Atomic Structure.- 2. Theoretical Basis of Chemical Shifts of Core Electrons.- 2.1. Valence Shell Potential Model.- 2.2. Effect of Neighboring Atoms.- 2.3. Calculation of Net Charge from Electronegativity.- 2.4. Calculation of Net Charge from Semiempirical MO.- 2.5. Use of Ab Initio Calculations for Chemical Shifts.- 2.6. Correlation of Chemical Shift with Thermochemical Data.- 3. Summary of Data on Chemical Shifts as a Function of the Periodic Table.- 3.1. Carbon.- 3.2. Nitrogen and Phosphorus.- 3.3. Sulfur and Oxygen.- 3.4. Group IIIA, IVA, VA, and VIA Elements.- 3.4.1. Group IIIA: B, Al, Ga, In, and Tl.- 3.4.2. Group IVA: C, Si, Ge, Sn, and Pb.- 3.4.3. Group VA: N, P, As, Sb, and Bi.- 3.4.4. Group VIA: O, S, Se, and Te.- 3.5. Halides and Rare Gases.- 3.6. Alkali Metals and Alkaline Earths.- 3.7. Transition Metals.- 3.7.1. First Transition Metal Series: Sc, Ti, V, Cr, Mn, Fe, Co, Ni.- 3.7.2. Second Transition Metal Series: Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd.- 3.7.3. Third Transition Metal Series: Hf, Ta, W, Re, Os, Ir, Pt.- 3.8. Groups IB and IIB: Cu, Ag, Au, Zn, Cd, Hg.- 3.9. Rare Earths and Actinides.- 4. Special Topics on Shifts in Core Binding Energies.- 4.1. Experimental and Interpretive Problems in PESIS.- 4.1.1. Comparative Problems in the Gas and Solid Phases.- 4.1.2. Charging.- 4.1.3. Definition of Binding Energy for Insulators.- 4.1.4. Binding Energy of Surface Atoms.- 4.1.5. Radiation Effects.- 4.1.6. Linewidths.- 4.2. Inorganic Compounds.- 4.2.1. Multiple Chemical Environment.- 4.2.2. Coordination Complexes.- 4.3. Organic Compounds.- 4.3.1. Resonance.- 4.3.2. Substituent Effects.- 4.3.3. Group Analysis.- 4.3.4. Specific Studies on Organic Molecules.- 4.4. Comparison of Core Electron Binding Energy Shifts with Other Physical Quantities.- 4.4.1. Mossbauer Isomer Shift.- 4.4.2. NMR.- 4.4.3. Other Physical Data.- 5. Other Applications of PESIS.- 5.1. Multicomponent Structure.- 5.1.1. Multiplet or Exchange Splitting.- 5.1.2. Electron Shakeoff and Shakeup.- 5.1.3. Configuration Interaction.- 5.1.4. Characteristic Energy Losses.- 5.1.5. Determining the Nature of Multicomponent Structure.- 5.2. PESIS for Surface Studies.- 5.3. Angular Studies with PESIS.- 6. Use of PESIS for Applied Research.- 6.1. PESIS as an Analytical Tool.- 6.2. Biological Systems.- 6.3. Geology.- 6.4. Environmental Studies.- 6.5. Surface Studies.- 6.6. Polymers and Alloys.- 6.7. Radiation Studies.- 6.8. Industrial Uses.- 6 Auger Electron Spectroscopy.- 1. Theory of the Auger Process.- 2. Comparison of the Auger Phenomenon with the Photoelectric Effect and X-Ray Emission.- 3. Use of Auger Spectroscopy for Gases.- 3.1. Atoms.- 3.2. Molecules.- 3.3. Study of Ionization Phenomena by Auger Spectroscopy.- 3.4. Autoionization.- 3.5. Auger Spectroscopy for Use in Gas Analysis.- 4. Use of Auger Spectroscopy in the Study of Solids.- 4.1. Special Problems Encountered on Using AES with Solids.- 4.1.1. Variables Concerned with Production of Auger Electrons.- 4.1.2. High-Energy Satellite Lines.- 4.1.3. Characteristic Energy Losses.- 4.1.4. Charging in Nonconducting Samples.- 4.2. High-Resolution Auger Spectroscopy with Solids.- 4.3. General Analytical Use of Auger Spectroscopy.- 4.4. Use of Auger Spectroscopy in the Study of Surfaces.- 4.4.1. General Considerations.- 4.4.2. Literature Survey of Surface Applications.- 4.5. Other Methods for Surface Analysis.- 4.5.1. Comparison of PESIS and Auger Spectroscopy for Surface Studies.- 4.5.2. Methods of Surface Analysis Other than AES and PESIS.- Appendixes.- 1. Atomic Binding Energies for Each Subshell for Elements Z = 1-106.- 3. Compilation of Data on Shifts in Core Binding Energies.- 4. Acronyms and Definitions of Special Interest in Electron Spectroscopy.- References.

Growth of Crystals

Abstract: Growth and Doping of Semiconductor Compounds: Kinetics of Incorporation Processes at Kink Sites YuYu Hervieu, MP Ruzaikin Gas-Phase Growth Kinetics and Morphology of Lead and Germanium Telluride Crystals LV Yashina, VI Dernovskii, VP Zlomanov, VI Shtanov Lateral Epitaxy of Gallium Arsenide by Chloride Vapor Transport IV Ivonin, LG Lavrent'eva, LP Porokhovnichenko Growth and Structure of Si Epilayers on Porous Si AA Fedorov, MA Revenko, EM Trukhanov, SI Romanov, AA Karanovich, VV Kirienko, MA Lamin, AK Gutakovskii, OP Pchelyakov, LV Sokolov Heteroepitaxy of Heterovalent Compounds: Molecular Beam Deposition of ZnSe on GaAs MV Yakushev, YuG Sidorov, LV Sokolov, VG Kesler, LM Logvinskii, TA Gavrilova Effect of Crystallographic Orientation of the Interface on the Growth of Perfect Epitaxial Layers of Semiconductors EM Trukhanov, AV Kolesnikov, GA Lyubas InGaAsP Solid Solutions: Phase Diagrams, Growth from the Melt on GaAs Substrates, Elastically Strained Epitaxial Layers YuB Bolkhovityanov, AS Yaroshevich, MA Revenko, EM Trukhanov Theory of Island Film Growth from a Eutectic Melt at the Late Stage of Evolution SA Kukushki, DA Grigor'ev Self-Sustained Nuclei-Assisted Explosive Crystallization VP Koverda, VN Skokov Morphological Instability and Inclusion Formation during Crystal Growth from a Flowing Solution SYu Potapenko Mechanisms of Striation Formation in Layer Growth of Crystals from Solutions IL Smolsky, AE Voloshin, EB Rudneva, NP Zaitseva, J De Yoreo Block Formation and Crystallographic Orientation Changes during Growth of Shaped Sapphire Single Crystals PI Antonov, SI Bakholdin, VM Krymov, IL Shul'pina, MP Shcheglov Revised Phase Diagrams of LiF-RF3 (R = La-Lu, Y) Systems PP Fedorov, BP Sobolev, LV Medvedeva, BM Reiterov The Growth of Laser Oxide Crystals: Structural Aspects EV Zharikov, GM Kuz'micheva, SG Novikov Vibrational Control of Czochralski Crystal Growth AZ Myal'dun, AI Prostomolotov, NK Tolochko, NA Verezub, EV Zharikov Ingrown Regular Domain Structure and Impurity Distribution in LiNbO3 Doped with a Rare Earth (Nd,Eu) and Magnesium II Naumova, NF Evlanova, OA Gliko, AA Lukashev, SV Lavrishchev

Electronic Core Levels of the II B − VI A Compounds

Abstract: X-ray induced electron-emission measurements were used to determine the energy levels of core electrons in ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgS, HgSe, and HgTe. The investigated energy range extends from the bottom of the valence band to about 1200 eV below the Fermi level. Chemical shifts were determined by comparing our results with experimental values for the pure elements. These shifts are plotted as a function of the fractional ionicity values determined by Phillips and Van Vechten, Pauling, and Coulson. Spinorbit-splitting values were experimentally determined for the first time for several levels including the $\mathrm{Zn}3d$, $\mathrm{Cd}4d$, and $\mathrm{Hg}5d$ levels. Furthermore, our measured energy values for these levels are used to determine the absolute energy values of the initial and final states of transitions normally labeled ${d}_{2}$ in ultraviolet reflectivity and electron-energy-loss measurements. Our results for ZnSe and CdTe are compared with self-consistent relativistic orthogonalized-plane-wave calculations for the excitation energies of these compounds. Agreement with these theoretical calculations is best for the levels closest to the valence band and appears to be angular momentum dependent.