InGaN micro-LEDs integrated onto an ultra-thin, colloidal quantum dot functionalized glass platform

We demonstrate an integrated color-converting device by transfer printing blue-emitting micro-sized InGaN LEDs onto an ultra-thin glass platform functionally enhanced with colloidal quantum dots. Color conversion and waveguiding properties of the structure are presented

Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

In this work, we have compared SiNx passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiNx passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 104–105 to 107) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (Dit ) is reduced (from 4.86 to 0.90 × 1012 cm−2 eV−1), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiNx passivation after full device fabrication results in the reduction of Dit and improves the surface related current collapse

Ngrams and Engrams: the use of structural and conceptual features to discriminate between English translations of religious texts

In this paper, we present experiments using the Linguistic Inquiry and Word Count (LIWC) program, a ‘closed-class keyword’ (CCK) analysis and a ‘correspondence analysis’ (CA) to examine whether the Scientology texts of L. Ron Hubbard are linguistically and conceptually like those of other religions. A Kruskal–Wallis test comparing the frequencies of LIWC category words in the Scientology texts and the English translations of the texts of five other religions showed that there were eighteen categories for which the Scientology texts differed from the others, and between one and seventeen for the other religions. In the CCK experiment, keywords typical of each religion were found, both by comparing the religious texts with one another and with the Brown corpus of general English. The most typical keywords were looked up in a concordancer and were manually coded with conceptual tags. The set of categories found for the Scientology texts showed little overlap with those found for the others. Our CA experiments produced fairly clear clusters of texts by religion. Scientology texts were seen at one pole on the first factor, with Christian and Islamic texts at the other. It appears that, in several ways, the Scientology texts are dissimilar to the texts of some of the world's major religions

Matter-wave cavity gravimeter

We propose a gravimeter based on a matter-wave resonant cavity loaded with a Bose-Einstein condensate and closed with a sequence of periodic Raman pulses. The gravimeter sensitivity increases quickly with the number of cycles experienced by the condensate inside the cavity. The matter wave is refocused thanks to a spherical wave-front of the Raman pulses. This provides a transverse confinement of the condensate which is discussed in terms of a stability analysis. We develop the analogy of this device with a resonator in momentum space for matter waves.Comment: 15 pages, 6 Figures. The expression for the atomic mirror focal length has been corrected. Other minor corrections and actualizations to the previously published versio

Transfer printed multi-color integrated devices for visible light communication applications

Integrated multi-color devices for visible light communication applications are fabricated by transfer printing blue-emitting GaN light emitting diodes (LEDs) onto a green-emitting LED array and a colloidal quantum dot color-converter structure

Effects of surface plasma treatment on threshold voltage hysteresis and instability in metal-insulator-semiconductor (MIS) AlGaN/GaN heterostructure HEMTs

In a bid to understand the commonly observed hysteresis in the threshold voltage (VTH) in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors during forward gate bias stress, we have analyzed a series of measurements on devices with no surface treatment and with two different plasma treatments before the in-situ Al2O3 deposition. The observed changes between samples were quasi-equilibrium VTH, forward bias related VTH hysteresis, and electrical response to reverse bias stress. To explain these effects, a disorder induced gap state model, combined with a discrete level donor, at the dielectric/semiconductor interface was employed. Technology Computer-Aided Design modeling demonstrated the possible differences in the interface state distributions that could give a consistent explanation for the observations

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved