A histogram-based model, derived from exemplars, provides a pragmatic guide for image analysis and enhancement. In AREDS2, the best digital images matched the best film. Overall, however, digital provided lower contrast of retinal detail. Digital images taken with higher G-to-R ratio showed better brightness and contrast management. Optimization of images in the multicenter study helps standardize documentation of AMD (ClinicalTrials.gov NCT00345176).

Here, a controlled variation in the fixed charge density (NF) and thickness of aluminum oxide tunnel insulators is reported, and the impact on Schottky barrier height (ΦB) in metal–insulator–semiconductor (MIS) diodes is studied. Analysis of metal–aluminum oxide–silicon capacitor structures indicates a change in NF from +1 × 1012 cm−2 in as‐deposited films to −2 × 1012 cm−2 in annealed films. An analytical model and numerical device physics simulations are used to predict changes in ΦB ­based on these changes in NF and alumina thickness. Surprisingly, Mott–Schottky derived ΦB values did not follow the trends predicted by these electrostatic models. In fact, there seems to be no discernable effect of NF in diodes with alumina thicknesses below 2 nm, contrary to contactless measurements of the fixed charge of films of similar thickness. The ΦB trends are better explained by a dipole model. It is further shown that in as‐deposited MIS diodes, the dipole is a function of alumina layer thickness, whereas in annealed MIS diodes, the dipole and ΦB were roughly constant independent of alumina thickness. These data suggest a strategy by which the ΦB of MIS tunnel contacts can be controlled and which has implication for the design of electrical contacts.

A better understanding of amorphous aluminum oxide’s structure and electronic properties is obtained through combined experimental and computational approaches. Grazing incidence X-ray scattering measurements were carried out on aluminum oxide thin films grown using thermal atomic layer deposition. The corresponding pair distribution functions (PDFs) showed structures similar to previously reported PDFs of solid-state amorphous alumina and molten alumina. Structural models based on crystalline alumina polymorphs (PDFgui) and amorphous alumina (molecular dynamics, MD) were examined for structural comparisons to the experimental PDF data. Smaller MD models were optimized and verified against larger models to allow for quantum chemical electronic structure calculations. The electronic structure of the amorphous alumina models yields additional insight into the band structure and electronic defects present in amorphous alumina that are not present in crystalline samples.

Dual-liquid-junction photoelectrochemistry and finite-element computational modeling quantified the effect on open-circuit photovoltage, V oc , of varying barrier heights at the back, traditionally ohmic contact to a semiconductor. Variations in experimental back-contact barrier heights included changes in the redox potential energy of the contacting phase afforded by a series of nonaqueous, metallocene-based redox couples that demonstrate facile, one-electron transfer and dipole-based band edge shifts due changes in the chemical species at the semiconductor surface. Variation in semiconductor surface chemistry included hydrogen-terminated Si(111) as well as methyl-terminated Si( 111) that yields a shift in band-edge alignment of ∼0.3 eV relative to hydrogen termination. While methylation of n-Si improves V oc values at rectifying contacts, methylation at an ohmic contact has a deleterious impact on V oc values. We discuss the present experimental and computational results in the context of non-ideal semiconductor contacts.