Highly electronegative metallic contacts to semiconductors using polymeric sulfur nitride

The Schottky barriers formed on n‐ZnS and n‐ZnSe by polymeric sulfur nitride have been compared to barriers formed by Au. Barrier energies as determined by photoresponse, current‐voltage, and capacitance‐voltage methods show that (SN)_x is approximately 1.0 eV higher than Au on n‐ZnS and 0.3–0.4 eV higher than Au on n‐ZnSe. We believe that this is the first report of any metallic contact more electronegative than Au

HgSe, a highly electronegative stable metallic contact for semiconductor devices

Schottky barriers formed by the highly electronegative substance HgSe on n-ZnS and on n-ZnSe have been characterized by capacitance-voltage and photoresponse measurements. The barriers are about 0.5 eV greater than Au barriers on these n-type substrates. HgSe contacts are stable under ambient conditions and are easily fabricated, making them attractive for device use

Growth and characterization of ZnTe films grown on GaAs, InAs, GaSb, and ZnTe

We report the successful growth of ZnTe on nearly lattice-matched III-V buffer layers of InAs (0.75%), GaSb (0.15%), and on GaAs and ZnTe by molecular beam epitaxy. In situ reflection high-energy electron diffraction measurements showed the characteristic streak patterns indicative of two-dimensional growth. Photoluminescence measurements on these films show strong and sharp features near the band edge with no detectable luminescence at longer wavelengths. The integrated photoluminescence intensity from the ZnTe layers increased with better lattice match to the buffer layer. The ZnTe epilayers grown on high-purity ZnTe substrates exhibited stronger luminescence than the substrates. We observe narrow luminescence linewidths (full width at half maximum ~ 1–2 Å) indicative of uniform high quality growth. Secondary-ion mass spectroscopy and electron microprobe measurements, however, reveal substantial outdiffusion of Ga and In for growths on the III-V buffer layers

Germanium Saturated with Gallium Antimonide

Single crystals of Ge saturated with GaSb were prepared by temperature gradient zone melting at 750°C. Electron probe microanalysis indicated 4.83×10^20 Ga atoms and 2.36×10^20 Sb atoms/cc in the saturated material with an estimated error of about 10%. Thus the solubility of Sb is greatly enhanced by the presence of Ga, though the reverse is not true. Hall measurements were in semiquantitative agreement with the chemical concentration measurements and indicated that carrier mobility is not much affected by the presence of the compensating impurity

Reactions in Crystalline Lattices: Chemistry of Lower Valence States of Lanthanides

Reduction of rare-earth (RE) ions to lower valence states in ionic crystals is described in terms of the equilibrium distribution theory for the (alkali halide):RE2+ and (alkaline-earth halide):RE3+ systems. Thermoluminescence glow curves of radiation-reduced CaF2:RE3+ systems reveal that the reoxidation of the divalent ions apparently occurs through thermal excitation of an f electron to the d bands. The additive reduction of RE2+ to the monovalent state in alkali halides yields striking results: While Sm1+ ions in KCl obtained by gamma radiation give rise to broad-band optical spectra which were attributed to 4f66s1 --> 4f56s2 transitions, those obtained through high-temperature additive treatment with liquid K give rise to narrow-line spectra that are not easily interpreted. These results illustrate well the major differences between the radiation reduction and additive reduction processes

Summary Abstract: Band offsets at HgTe CdTe interfaces

Band offsets are an important physical characteristic of any heterojunction. The HgTe-CdTe offset is particularly important since it affects the properties of the superlattice which is under much investigation theoretically and experimentally (1,2). To measure band offsets an abrupt interface is necessary, requiring limited interdiffusion between each material. This requires a low temperature technique to grow a HgTe epitaxial layer on CdTe. Conventional Te-rich liquid-phase epitaxy (LPE) has too much interdiffusion for a menaingful measurement. Metal-organic chemical vapor deposition (MOCVD) which can be done at 325 °C possibly has too much interdiffusion (3). Up until now the lowest temperature growth technique has been molecular beam epitaxy (MBE) which grows in the range 120-200 °C with best epitaxy near 200 °C (4). Below is a description of a novel Hg-rich LPE technique which also gives growth in the range 125-200 °C