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New Zealand apple exports must meet strict phytosanitary measures to eliminate codling moth (Cydia pomonella Linnaeus) (Lepidoptera: Tortricidae) larval infestation. This study was part of a program attempting the localized eradication of codling moth within an isolated cluster of seven orchards (391 ha). A conventional management program of insecticide sprays and pheromone mating disruption was supplemented with weekly releases of sterile moths for 1–6 yr. Our objective was to compare the recapture rate of sterile moths following their release by four methods, and the efficiency of each system. The methods were the following: a fixed-wing unmanned plane flying ~40–45 m high at 70 km/h, an unmanned hexacopter travelling 20 m high at 25 km/h, and manually from the ground via bicycles or motor vehicles. The different release methods were used in different years or weeks. Sterile male moths were recaptured in grids of pheromone traps positioned throughout each orchard. The highest recapture rate followed delivery by hexacopter, then bicycle, vehicle, and plane. There was a 17-fold difference in catches between releases by hexacopter and plane, and sixfold between vehicle and plane in the same season. Bicycle delivery had a 3.5-fold higher recapture rate than the plane in different years. The wind-borne horizontal drift of moths was investigated as a possible explanation for the disparity of recaptures between the two aircraft delivery systems. The methods in ascending order of time per hectare for delivery were the following: plane and vehicle, hexacopter, then bicycle. The advantages and disadvantages of each moth delivery method are discussed.

We report on the discovery and validation of TOI 813b (TIC 55525572 b), a transiting exoplanet identified by citizen scientists in data from NASA's Transiting Exoplanet Survey Satellite (TESS) and the first planet discovered by the Planet Hunters TESS project. The host star is a bright (V = 10.3 mag) subgiant ($R_\star=1.94\,R_\odot$, $M_\star=1.32\,M_\odot$). It was observed almost continuously by TESS during its first year of operations, during which time four individual transit events were detected. The candidate passed all the standard light curve-based vetting checks, and ground-based follow-up spectroscopy and speckle imaging enabled us to place an upper limit of $2 M_{Jup}$ (99 % confidence) on the mass of the companion, and to statistically validate its planetary nature. Detailed modelling of the transits yields a period of $83.8911_{ - 0.0031 } ^ { + 0.0027 }$ days, a planet radius of $6.71 \pm 0.38$ $R_{\oplus}$, and a semi major axis of $0.423_{ - 0.037 } ^ { + 0.031 }$ AU. The planet's orbital period combined with the evolved nature of the host star places this object in a relatively under-explored region of parameter space. We estimate that TOI-813b induces a reflex motion in its host star with a semi-amplitude of $\sim6$ ms$^{-1}$, making this system a promising target to measure the mass of a relatively long-period transiting planet., Accepted for publication in MNRAS (16 pages, 10 figures, 3 tables)

Staggered back-gated Field Effect Transistor (FET) structures were made by growing Li-doped NiO on Si3N4/SiO2/Si (111) using room temperature pulsed laser deposition. Optical studies showed over 80% transmission for the NiO:Li channel at wavelengths > 500nm. The MISFET revealed rectifying transfer characteristics, with a VON close to zero, a channel mobility of ~ 1 cm2/Vs, a gate leakage current (at +5V) of 0.8 mA and an ION/IOFF ratio (at a Vgs of -15V) of ~ 103. The transistors showed enhancement-mode output characteristics indicative of a p-type channel with sharp pinchoff, hard saturation, a comparatively high (milliampere range) Id and a relatively low on-resistance of ~11 kΩ. Hence the adoption of Li doping in NiO channels would appear to be a promising approach to obtain p-type TFTs with superior transparency, speed and energy efficiency.

Codling moth was introduced into New Zealand, and remains a critical pest for the apple industry. Apples exported to some markets require strict phytosanitary measures to eliminate the risk of larval infestation. Mating disruption and insecticide applications are the principal means of suppression in New Zealand. We tested the potential for the sterile insect technique (SIT) to supplement these measures to achieve local eradication or suppression of this pest. SIT was trialed in an isolated group of six integrated fruit production (IFP) orchards and one organic orchard (total 391 ha), using sterilized insects imported from Canada, with release by unmanned aerial vehicle and from the ground. Eradication was not achieved across the region, but a very high level of codling moth suppression was achieved at individual orchards after the introduction of sterile moths in combination with mating disruption and larvicides. After six years of releases, catches of wild codling moths at three IFP orchards (224 ha) were 90&ndash, 99% lower than in 2013&ndash, 2014, the year before releases began. Catches at three other IFP orchards (129 ha) decreased by 67&ndash, 97% from the year before releases began (2015&ndash, 2016), from lower initial levels. At a certified organic orchard with a higher initial population under only organic larvicides and mating disruption, by 2019&ndash, 2020, there was an 81% reduction in wild moths capture from 2016&ndash, 2017, the year before releases began.

p-GaN/i-InGaN/n-GaN (PIN) structures were grown epitaxially on ZnO-buffered c-sapphire substrates by metal organic vapor phase epitaxy using the industry standard ammonia precursor for nitrogen. Scanning electron microscopy revealed continuous layers with a smooth interface between GaN and ZnO and no evidence of ZnO back-etching. Energy Dispersive X-ray Spectroscopy revealed a peak indium content of just under 5 at% in the active layers. The PIN structure was lifted off the sapphire by selectively etching away the ZnO buffer in an acid and then direct bonded onto a glass substrate. Detailed high resolution transmission electron microscoy and grazing incidence X-ray diffraction studies revealed that the structural quality of the PIN structures was preserved during the transfer process.

The sterile insect technique (SIT) is increasingly being evaluated as a potential complementary strategy for pest suppression or elimination New Zealands export fruit sector has an imperative to meet strict international phytosanitary requirements together with increasing market demand for residuefree produce SIT is a pestspecific method of insect control that can complement current Integrated Pest Management (IPM) strategies Successful SIT presents significant challenges the target pest must be a good candidate for suppression and strong stakeholder and community commitment is required to achieve and maintain suppression until areawide elimination is achieved Emerging sterilisation technologies and refinement of existing methods are making this technology progressively more efficient and costeffective This study reviewed the advantages of including SIT in an IPM programme and described the first use of codling moth SIT in New Zealand A pilot programme is currently underway to evaluate its potential to achieve local elimination of codling moth in Central Hawkes Bay apple orchards

The bandgap of wurzite ZnO layers grown on 2 inch diameter c-Al2O3 substrates by pulsed laser deposition was engineered from 3.7 to 4.8 eV by alloying with Mg. Above this Mg content the layers transformed from single phase hcp to mixed hcp/fcc phase before becoming single phase fcc above a bandgap of about 5.5 eV. Metal-Semiconductor-Metal (MSM) photodetectors based on gold Inter-Digitated-Transducer structures were fabricated from the single phase hcp layers by single step negative photolithography and then packaged in TO5 cans. The devices gave over 6 orders of magnitude of separation between dark and light signal with solar rejection ratios (I270 : I350) of over 3 × 105 and dark signals of 300 pA (at a bias of -5V). Spectral responsivities were engineered to fit the “Deutscher Verein des Gas- und Wasserfaches” industry standard form and gave over two decade higher responsivities (14 A/W, peaked at 270 nm) than commercial SiC based devices. Homogeneous Ga2O3 layers were also grown on 2 inch diameter c-Al2O3 substrates by PLD. Optical transmission spectra were coherent with a bandgap that increased from 4.9 to 5.4 eV when film thickness was decreased from 825 to 145 nm. X-ray diffraction revealed that the films were of the β-Ga2O3 (monoclinic) polytype with strong (-201) orientation. β-Ga2O3 MSM photodetectors gave over 4 orders of magnitude of separation between dark and light signal (at -5V bias) with dark currents of 250 pA and spectral responsivities of up to 40 A/W (at -0.75V bias). It was found that the spectral responsivity peak position could be decreased from 250 to 230 nm by reducing film thickness from 825 to 145 nm. This shift in peak responsivity wavelength with film thickness (a) was coherent with the apparent bandgap shift that was observed in transmission spectroscopy for the same layers and (b) conveniently provides a coverage of the spectral region in which MgZnO layers show fcc/hcp phase mixing.

International audience; GaN is a durable, radiation hard and wide-bandgap semiconductor material, making it ideal for usage with betavoltaic batteries. This paper describes the design, fabrication and experimental testing of 1 cm$^2$ GaN-based betavoltaic batteries (that achieve an output power of 2.23 nW) along with a full model that accurately simulates the device performance which is the highest to date (to the best of our knowledge) for GaN-based devices with a $^{Ni}$63 source.

Self-forming, vertically-aligned, ZnO moth-eye-like nanoarrays were grown by catalyst-free pulsed laser deposition on a-SiO2/Si (1 1 1) substrates. X-Ray Diffraction (XRD) and Cathodoluminescence (CL) studies indicated that nanostructures were highly c-axis oriented wurtzite ZnO with strong near band edge emission. The nanostructures were used as templates for the growth of non-polar GaN by metal organic vapor phase epitaxy. XRD, scanning electron microscopy, energy dispersive X-ray microanalysis and CL revealed ZnO encapsulated with GaN, without evidence of ZnO back-etching. XRD showed compressive epitaxial strain in the GaN, which is conducive to stabilization of the higher indium contents required for more efficient green light emitting diode (LED) and photovoltaic (PV) operation. Angular-dependent specular reflection measurements showed a relative reflectance of less than 1% over the wavelength range of 400–720 nm at all angles up to 60°. The superior black-body performance of this moth-eye-like structure would boost LED light extraction and PV anti-reflection performance compared with existing planar or nanowire LED and PV morphologies. The enhancement in core conductivity, provided by the ZnO, would also improve current distribution and increase the effective junction area compared with nanowire devices based solely on GaN.

We investigate the optical signature of the interface in a single MgZnO/ZnO heterojunction, which exhibits two orders of magnitude lower resistivity and 10 times higher electron mobility compared with the MgZnO/Al2O3 film grown under the same conditions. These impressive transport properties are attributed to increased mobility of electrons at the MgZnO/ZnO heterojunction interface. Depth-resolved cathodoluminescence and photoluminescence studies reveal a 3.2 eV H-band optical emission from the heterointerface, which exhibits excitonic properties and a localization energy of 19.6 meV. The emission is attributed to band-bending due to the polarization discontinuity at the interface, which leads to formation of a triangular quantum well and localized excitons by electrostatic coupling.

Brillouin light scattering (BLS) was conducted on melt-grown ZnO bulk crystals and ZnO thin films grown by pulsed laser deposition. The bulk ZnO crystals presented both longitudinal and transverse bulk acoustic waves. Theoretical calculations agreed well with there being one piezoelectric longitudinal branch and two transverse branches. BLS measurements conducted on ZnO thin films also revealed Rayleigh surface acoustic waves (R-SAW) guided by only the surface of the layer and Sezawa modes, guided by the film thickness. Measurements were conducted for three incidence angles in order to investigate different SAW wave numbers. Higher frequency features were identified as being related to a new class of guided longitudinal (LG) SAW modes which are not usually detected for ZnO thin films. The LG-SAW modes were observed for two incidence angles (θ=45° and 55°) corresponding to frequencies of 17.88 and 20.75 GHz, respectively. BLS measurements enable us to estimate the LG-SAW velocity as 6500 m/s. This value is three times higher than that of the currently used R-SAW. Theoretical simulations were coherent with the presence of LG modes in the ZnO layers. Such LG-SAW modes are promising for the development of novel, higher-speed SAW devices operating in the GHz-band and which could be readily incorporated in Si-based integrated circuitry.

International audience; Eight 1 cm 2 samples of self-organising zinc oxide (ZnO) nanopillar arrays with preferential vertical orientation were grown by pulsed laser deposition and then coated with 30 nm of Au using either thermal or electron-beam evaporation. Each sample had a different set of ZnO and Au growth conditions. The Au/ZnO nanoarrays were then tested for use in surface enhanced Raman scattering (SERS) detection of thiophenol molecules. The ratio of I SERS /I Raman was adopted as a measure of the SERS sensitivity and was found to vary from 1.7 to 23.7 within the 8 samples. The impact of the density, width, filling factor, orientation, homogeneity and shape of the nanostructures on the average SERS intensity and the within-wafer reproducibility of the SERS response were considered for 9 paired comparisons based on fixing all but one of the growth parameters for each pairing. Overall, smaller nanopillar width was found to correlate with stronger average SERS signal while more vertically aligned arrays with higher filling factors showed better within-wafer reproducibility.

Nominally-undoped Ga 2 O 3 layers were deposited on a -, c - and r -plane sapphire substrates using pulsed laser deposition. Conventional x-ray diffraction analysis for films grown on a - and c -plane sapphire showed the layers to be in the β-Ga 2 O 3 phase with preferential orientation of the (-201) axis along the growth direction. Pole figures revealed the film grown on r-plane sapphire to also be in theβ-Ga 2 O 3 phase but with epitaxial offsets of 29.5°, 38.5° and 64° from the growth direction for the (-201) axis. Optical transmission spectroscopy indicated that the bandgap was ~5.2eV, for all the layers and that the transparency was > 80% in the visible wavelength range. Four point collinear resistivity and Van der Pauw based Hall measurements revealed the β-Ga 2 O 3 layer on r -plane sapphire to be 4 orders of magnitude more conducting than layers grown on a - and c -plane sapphire under similar conditions. The absolute values of conductivity, carrier mobility and carrier concentration for the β-Ga 2 O 3 layer on r -sapphire (at 20Ω -1 .cm -1 , 6 cm 2 /Vs and 1.7 x 10 19 cm -3 , respectively) all exceeded values found in the literature for nominally-undoped β-Ga 2 O 3 thin films by at least an order of magnitude. Gas discharge optical emission spectroscopy compositional depth profiling for common shallow donor impurities (Cl, F, Si and Sn) did not indicate any discernable increase in their concentrations compared to background levels in the sapphire substrate. It is proposed that the fundamentally anisotropic conductivity in β-Ga 2 O 3 combined with the epitaxial offset of the (-201) axis observed for the layer grown on r -plane sapphire may explain the much larger carrier concentration, electrical conductivity and mobility compared with layers having the (-201) axis aligned along the growth direction.

Eucolaspis sp. “Hawke's Bay” (Chrysomelidae: Eumolpinae) is a pest that inflicts huge economic loss in many organic apple (Malus domestica Borkh.) orchards in New Zealand. The timing of control methods for this pest has been shown to be crucial for success. To aid in planning control programs, we studied threshold temperature and degree-days required for the development of Eucolaspis sp. “Hawke's Bay” pupae and modeled adult emergence in the field. Pupal development was observed at three constant temperatures. Pupae required 237.0 ± 21.67 degree-days above lower threshold temperature of 4.7°C ± 0.89°C to develop into adults. The emergence of adults was modeled with these thermal values and the model was tested for accuracy with field data. The model performed well with a precision of ±4 d. The proposed phenology model has wide applicability in monitoring and planning pest control measures.

Codling moth, although rare on New Zealand export pipfruit, is a quarantine actionable pest that limits access to countries where it is not present and requires speciic control measures during production. Fumigation with phosphine gas is a disinfestation technology that has recently been extended to fresh produce. Apples infested with codling moth ifth instar larvae and eggs were fumigated for two durations at concentrations from 500 to 3500 ppm phosphine at two temperatures. Larval mortality assessed 3 days post fumigation at 0.5°C increased with increasing dose, with little difference between 48- and 72-h treatments. In contrast, mortality after fumigation of larvae at 12°C did not increase with dose and resulted in overall higher mortality than 0.5°C. Codling moth eggs were more susceptible to fumigation at 0.5°C than at 12°C; fumigation at 12°C had minimal effect at all doses. The implications for improved market access using phosphine fumigation are discussed.

OBJECTIVES: Malaria risk maps have re-emerged as an important tool for appropriately targeting the limited resources available for malaria control. In Sub-Saharan Africa empirically derived maps using standardized criteria are few and this paper considers the development of a model of malaria risk for East Africa. METHODS: Statistical techniques were applied to high spatial resolution remotely sensed, human settlement and land-use data to predict the intensity of malaria transmission as defined according to the childhood parasite ratio (PR) in East Africa. Discriminant analysis was used to train environmental and human settlement predictor variables to distinguish between four classes of PR risk shown to relate to disease outcomes in the region. RESULTS: Independent empirical estimates of the PR were identified from Kenya, Tanzania and Uganda (n = 330). Surrogate markers of climate recorded on-board earth orbiting satellites, population settlement, elevation and water bodies all contributed significantly to the predictive models of malaria transmission intensity in the sub-region. The accuracy of the model was increased by stratifying East Africa into two ecological zones. In addition, the inclusion of urbanization as a predictor of malaria prevalence, whilst reducing formal accuracy statistics, nevertheless improved the consistency of the predictive map with expert opinion malaria maps. The overall accuracy achieved with ecological zone and urban stratification was 62% with surrogates of precipitation and temperature being among the most discriminating predictors of the PR. CONCLUSIONS: It is possible to achieve a high degree of predictive accuracy for Plasmodium falciparum parasite prevalence in East Africa using high-spatial resolution environmental data. However, discrepancies were evident from mapped outputs from the models which were largely due to poor coverage of malaria training data and the comparable spatial resolution of predictor data. These deficiencies will only be addressed by more random, intensive small areas studies of empirical estimates of PR.

The parasitoid Aphelinus mali controls woolly apple aphid (WAA; Eriosoma lanigerum) in New Zealand apple orchards. The effects of seven pesticides on A. mali exposed to residues on filter paper were assessed in a laboratory bioassay immediately post- application. Spinosad at label rate was moderately to highly toxic, but other compounds and lower rates of spinosad had no detrimental effects on A. mali. Another bioassay incorporating field application and exposure to aged residues on leaves determined the toxicity of carbaryl, diazinon, indoxacarb and lime sulphur. Carbaryl had the greatest residual toxicity to A. mali on harvested leaves, causing 85% mortality 21 days after application, declining to 40% by 28 days. In contrast, diazinon initially caused high mortality but residues were not toxic 15 days after application, while indoxyacarb and lime sulphur were not toxic. Minimising the use of pesticides toxic to A. mali should benefit the sustainable management of WAA in apple orchards.

Leafrollers are important pests of apples and infested fruit can result in rejection of export consignments. Leafroller mating disruption using a pheromone blend with activity against three species was examined in 12 Hawke's Bay orchards over two seasons (2009- 10 and 2010-11). Pheromone dispensers (600/ha) and a single insecticide were applied to trees in early November, and subsequent insecticide use was based on leafroller pheromone trapping and thresholds. The pheromone blend substantially suppressed mating of virgin female lightbrown apple moth in treated orchards and reduced male catch in pheromone traps by up to 98% compared with the season prior to implementation. Insecticide use for leafroller control decreased accordingly, from 2.1-2.7 insecticides per block in 2008/09 to 1.0-1.8 in 2010/11. Leafroller control using mating disruption was acceptable, fruit damage varied from 0.3% to 0.16% and no leafroller larvae were found on fruit in both field assessments and phytosanitary inspections of packed cartons.

ZnO nanostructures were grown by pulsed laser deposition on c-sapphire, Si (111) (n-type and p-type) and analysed using morphological and optical techniques. Under optimized growth conditions, self-forming arrays of vertically aligned nanostructures were obtained. Scanning electron microscopy studies revealed two main structures: nanocolumns and a 'moth-eye type' array of nanocones, which gave a graded effective refractive index. X-ray diffraction measurements indicate that both types of structures are highly oriented along the c-axis. The optical properties were investigated using low temperature photoluminescence (PL) and room temperature (RT) reflection measurements. Low temperature PL spectra for nanocolumns grown on sapphire and n-type Si showed an emission which is similar to that observed for bulk ZnO with a spectrum dominated by donor bound exciton recombination at ∼3.36eV and a structured green band. The PL intensity was particularly enhanced for nanocone structures grown on cubic Si substrates. For these samples, additional features, which are not observed for bulk ZnO were observed at 3.12, 3.02 and 2.92 eV following a vibronic progression of 100 meV. RT angular-dependent specular reflection measurements indicated that all the nanostructures act as highly effective broadband antireflection coatings.

New Zealand’s major fruit industries are dependent upon producing high-quality crops for export with a very low incidence of pest damage. Light brown apple moth was an economically important pest within the fruit sector in the 1960s through the 1980s, and it developed resistance to broad-spectrum insecticides. The increase in its pest status focused research on biological control, and existing native natural enemies were augmented with new introductions from Australia in the late 1960s. By the early 1990s, this effort resulted in substantially reduced leafroller populations and fruit damage. The implementation of integrated pest management (IPM) programs in the New Zealand fruit sector in the mid- to late 1990s practically eliminated the use of broad-spectrum organophosphate insecticides, further enhancing natural control. Today light brown apple moth is successfully managed in IPM and organic programs through a combination of biological control and threshold-based applications of selective insecticides.

n-ZnO/p-GaN:Mg hybrid heterojunctions grown on c-Al2O3 substrates showed 375 nm room temperature electroluminescence. It was suggested that the high materials and interface quality obtained using pulsed laser deposition for the n-ZnO growth and metal–organic chemical vapor deposition for the p-GaN:Mg were key factors enabling the injection of holes and the radiative near band edge recombination in the ZnO. In this paper we present the materials characterization of this structure using x-ray diffraction, scanning electron microscopy and atomic force microscopy.

Some X-ray scattering methods (X-ray reflectometry and Diffractometry) dedicated to the study of thin-layered heterostructures are presented with a particular focus, for practical purposes, on the description of fast, accurate and robust techniques. The use of X-ray scattering metrology as a routinely working non-destructive testing method, particularly by using procedures simplifying the data-evaluation, is emphasized. The model-independent Fourier-inversion method applied to a reflectivity curve allows a fast determination of the individual layer thicknesses. We demonstrate the capability of this method by reporting X-ray reflectometry study on multilayered oxide structures, even when the number of the layers constitutive of the stack is not known a-priori. Fast Fourier transform-based procedure has also been employed successfully on high resolution X-ray diffraction profiles. A study of the reliability of the integral-breadth methods in diffraction line-broadening analysis applied to thin layers, in order to determine coherent domain sizes, is also reported. Examples from studies of oxides-based thin-layers heterostructures will illustrate these methods. In particular, X-ray scattering studies performed on high-k HfO2 and SrZrO3 thin-layers, a (GaAs/AlOx) waveguide, and a ZnO thin-layer are reported.

Summary A survey of cotton (Gossypium hirsutum) volunteers was conducted along the 1400 km of a cottonseed transport route in north-east Australia to determine the extent of naturalisation from spilt seed. In each year, 1% of the road distance was inspected for volunteer plants. The survey results were juxtaposed with the eco-climatic suitability predictions from inferential modelling. Over 3 years, 22 cotton plants were found at eight sites. Within the cotton production region, volunteers averaged 2.28 plants km−1 of road; their most likely source was seed cotton spilt during the previous harvest. Further north, three plants were found over 3 years, at an average density of 0.089 plants km−1 of road; all three plants were found in locations with a positive Ecoclimatic Index. No secondary spread was detected. Roadside slashing reduced plant survival and the potential to produce seed. In the wet tropics, weed competition and slashing prevented volunteers establishing. The surveys indicate that roadsides in north-east Australia are a hostile environment for the establishment of cotton plants, with no evidence of naturalisation or secondary spread. Current transport practices utilizing fully covered loads present negligible risk of producing naturalised populations of cotton (either transgenic or non-transgenic) on roadsides in north-east Australia.

Luminescent nanoscale materials (LNMs) have received widespread interest in sensing and lighting applications due to their enhanced emissive properties. For sensing applications, LNMs offer improved sensitivity and fast response time which allow for lower limits of detection. Meanwhile, for lighting applications, LNMs, such as quantum dots, offer an improved internal quantum efficiency and controlled color rendering which allow for better lighting performances. Nevertheless, due to their nanometric dimensions, nanoscale materials suffer from extremely weak luminescence excitation (i.e. optical absorption) limiting their luminescence intensity, which in turn results in a downgrade in the limits of detection and external quantum efficiencies. Therefore, enhancing the luminescence excitation is a major issue for sensing and lighting applications. In this work, we report on a novel photonic approach to increase the luminescence excitation of nanoscale materials. Efficient luminescence excitation increase is achieved via a gain-assisted waveguided energy transfer (G-WET). The G-WET concept consists on placing nanoscale materials atop of a waveguiding active (i.e. luminescent) layer with optical gain. Efficient energy transfer is thus achieved by exciting the nanoscale material via the tail of the waveguided mode of the active layer emission. The G-WET concept is demonstrated on both a nanothin layer of fluorescent sensitive polymer and on CdSe/ZnS quantum dots coated on ZnO thin film, experimentally proving up to an 8-fold increase in the fluorescence of the polymer and a 3-fold increase in the luminescence of the CdSe/ZnS depending of the active layer emission regime (stimulated vs spontaneous emission). Furthermore, we will discuss on the extended G-WET concept which consists on coating nanoscale materials on a nanostructured active layer. The nanostructured active layer offers the necessary photonic modulation and a high specific surface which can presumably lead to a more efficient G-WET concept. Finally, the efficiency as well as the observation conditions of the GWET will be discussed and compared with more conventional charge transfer or dipole-dipole energy transfer.

(In)GaN p-i-n structures were grown by MOVPE on both GaN- and ZnO-coated c-sapphire substrates. XRD studies of the as-grown layers revealed that a strongly c-axis oriented wurtzite crystal structure was obtained on both templates and that there was a slight compressive strain in the ZnO underlayer which increased after GaN overgrowth. The InGaN peak position gave an estimate of 13.6at% for the indium content in the active layer. SEM and AFM revealed that the top surface morphologies were similar for both substrates, with an RMS roughness (5 μm x 5 μm) of about 10 nm. Granularity appeared slightly coarser (40nm for the device grown on ZnO vs 30nm for the device grown on the GaN template) however. CL revealed a weaker GaN near band edge UV emission peak and a stronger broad defect-related visible emission band for the structure grown on the GaN template. Only a strong ZnO NBE UV emission was observed for the sample grown on the ZnO template. Quarter-wafer chemical lift-off (CLO) of the InGaN-based p-i-n structures from the sapphire substrate was achieved by temporary-bonding the GaN surface to rigid glass support with wax and then selectively dissolving the ZnO in 0.1M HCl. XRD studies revealed that the epitaxial nature and strong preferential c-axis orientation of the layers had been maintained after lift-off. This demonstration of CLO scale-up, without compromising the crystallographic integrity of the (In)GaN p-i-n structure opens up the perspective of transferring GaN based devices off of sapphire substrates industrially.

NiO/ZnO heterostructures were fabricated on FTO/glass and bulk hydrothermal ZnO substrates by pulsed laser deposition. X-Ray diffraction and Room Temperature (RT) Raman studies were consistent with the formation of (0002) oriented wurtzite ZnO and (111) oriented fcc NiO. RT optical transmission studies revealed bandgap energy values of ~3.70 eV and ~3.30 eV for NiO and ZnO, respectively and more than 80% transmission for the whole ZnO/NiO/FTO/glass stack over the majority of the visible spectrum. Lateral p-n heterojunction mesas (~6mm x 6mm) were fabricated using a shadow mask during PLD growth. n-n and p-p measurements showed that Ti/Au contacting gave an Ohmic reponse for the NiO, ZnO and FTO. Both heterojunctions had rectifying I/V characteristics. The junction on FTO/glass gave forward bias currents (243mA at +10V) that were over 5 orders of magnitude higher than those for the junction formed on bulk ZnO. At ~ 10-7 A (for 10V of reverse bias) the heterojunction leakage current was approximately two orders of magnitude lower on the bulk ZnO substrate than on FTO. Overall, the lateral p-NiO/n- ZnO/FTO/glass device proved far superior to that formed by growing p-NiO directly on the bulk n-ZnO substrate and gave a combination of electrical performance and visible wavelength transparency that could predispose it for use in various third generation transparent electronics applications.

Eucolaspis Sharp 1886 is a New Zealand native leaf beetle genus (Coleoptera: Chrysomelidae: Eumolpinae) with poorly described species and a complex taxonomy. Many economically important fruit crops are severely damaged by these beetles. Uncertain species taxonomy of Eucolaspis is leaving any biological research, as well as pest management, tenuous. We used morphometrics, mitochondrial DNA and male genitalia to study phylogenetic and geographic diversity of Eucolaspis in New Zealand. Freshly collected beetles from several locations across their distribution range, as well as identified voucher specimens from major museum collections were examined to test the current classification. We also considered phylogenetic relationships among New Zealand and global Eumolpinae (Coleoptera: Chyrosomelidae). We demonstrate that most of the morphological information used previously to define New Zealand Eucolaspis species is insufficient. At the same time, we show that a combination of morphological and genetic evidence supports the existence of just 3 mainland Eucolaspis lineages (putative species), and not 5 or 15, as previously reported. In addition, there may be another closely related lineage (putative species) on an offshore location (Three Kings Islands, NZ). The cladistic structure among the lineages, conferred through mitochondrial DNA data, was well supported by differences in male genitalia. We found that only a single species (lineage) infests fruit orchards in Hawke’s Bay region of New Zealand. Species-host plant associations vary among different regions.

In this work we investigated ZnO films grown on semi-insulating (100) GaAs substrates by pulsed laser deposition. Samples were studied using techniques including X-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy, Raman spectroscopy, temperature dependent photoluminescence, C-V profiling and temperature dependent Hall measurements. The Hall measurements showed a clear p-type response with a relatively high mobility (∼260 cm2/V s) and a carrier concentration of ∼1.8 × 1019 cm–3. C-V profiling confirmed a p-type response. XRD and Raman spectroscopy indicated the presence of (0002) oriented wurtzite ZnO plus secondary phase(s) including (101) oriented Zn2As2O7. The results suggest that significant atomic mixing was occurring at the film/substrate interface for films grown at substrate temperatures of 450 oC (without post-annealing). (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Approximately 750000 P maculipennis (internal facultatively gregarious encyrtid parasitoids of the obscure mealybug (Pseudococcus viburni)) were released to 41 pipfruit orchards in Hawkes Bay Nelson/Motueka and Auckland and to the Wellington Botanic Gardens between 2001 and 2004 At least a year later they were recovered from 83 of the Hawkes Bay and 60 of the Nelson orchards and from the Wellington Botanic Gardens indicating that the parasitoid has a solid foothold in New Zealand Pseudaphycus maculipennis have dispersed since their release at a natural rate of about 200 m/year Laboratory massrearing production techniques for P maculipennis are described No measures of the impact of P maculipennis on obscure mealybug populations in orchards have yet been carried out

A laboratory bioassay was used to evaluate the effect of residues from 10 orchard pesticides on mortality of Dolichogenidea tasmanica a parasitoid of leafrollers Adult parasitoids were caged in Petri dishes that had been sprayed with the field rate of the pesticides Mortality was assessed over 7 days and classified using the laboratory criteria defined by the International Organization for Biological and Integrated Control of Noxious Animals and Plants Residues of buprofezin emamectin benzoate lufenuron tebufenozide and thiacloprid were harmless (lt;30 mortality) to D tasmanica adults in the 7 days after treatment Indoxacarb and lime sulphur residues were moderately harmful (8099 mortality) while carbaryl diazinon and spinosad residues were harmful (>99 mortality) The implications for leafroller control in pipfruit production programmes are discussed

The fate of apple leafcurling midge (ALCM Dasineura mali) egg batches was monitored in spring 2003 at two apple orchards in Riwaka near Motueka Orchard A had received prebloom insecticide applications of chlorpyrifos and carbaryl for fruit thinning each season since 2000 Orchard B substituted these chemicals with the selective insecticide buprofezin and used benzyladenine for fruit thinning over the same period Predation and parasitism of ALCM eggs at orchard B resulted in lower survival of larvae and less damage to shoots compared to orchard A Ninety percent of ALCM larvae at orchard B were parasitised by Platygaster demades compared with only 3 at orchard A Heavy infestation of shoots by second generation midge larvae at orchard A resulted in premature termination of 69 of growing shoot tips These results suggest that nonselective early season insecticides used in pipfruit spray programmes may disrupt biological control of ALCM

Pheromone traps have potential to assist with integrated pest management of diamondback moth (Plutella xylostella (Linnaeus)). Trapping experiments were set up in brassica crops in Canterbury and Auckland to test the potential for improving lures for pheromone traps. Catch was improved with higher purity of synthetic lures containing ( Z)-11-hexadecenyl acetate and (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol (30:60:10). The initial lures tested caught 7.5% of the number of moths caught in traps baited with virgin females. This increased to 20-47% using better lures. Coupled gas chromatography and electrophysiology confirmed the presence of three active peaks from the chemicals listed above, plus a fourth unidentified compound. Traps with improved lures were used in a pilot IPM programme in Pukekohe and will assist brassica growers to minimise insecticide usage.

Huhu beetle larvae, Prionoplus reticularis White, were successfully reared in the laboratory at 20°C L:D 0:24 h on an artificial diet containing pine sawdust. The larval period was reduced to c. 250 days compared with at least 2 years in the field. Mean larval weight increased from 1.38 mg (neonate) to 3639 mg (mature larvae) after 230 days on artificial diet. Most larvae entered diapause, which was successfully terminated by ambient field conditions in season but not by laboratory chilling regimes. The diet used may be suitable for other cerambycids, and especially useful for rearing field‐collected larvae to provide adult beetles for taxonomic studies.

International audience; Microdisks were fabricated in zinc oxide (ZnO) thin films using a top-down approach combining electron beam lithography and reactive ion etching. These microdisk structured thin films exhibit a stimulated surface emission between 3 and 7 times higher than that from a reference film depending on the excitation power density. Emission peak narrowing, reduction in lasing threshold and blue-shifting of the emission wavelength were observed along with enhancement in the emitted intensity. Results indicate that this enhancement is due to an increase in the internal quantum efficiency combined with an amplification of the stimulated emission. An analysis in terms of waveguiding is presented in order to explain these effects. These results demonstrate that very significant gains in emission can be obtained through conventional microstructuration without the need for more onerous top-down nanostructuration techniques.

Free-standing (0002)-oriented GaN substrates (φ = 2”) were coated with 200 nm of ZnO and used as templates for the growth of GaN thin films. SEM and AFM revealed that such GaN layers had a relatively homogenous surface morphology with an RMS roughness (5 μm x 5 μm) of less than 4nm. XRD studies revealed strained ZnO growth on the GaN substrate and the reproduction of the substrate rocking curve for the GaN overlayers after only a hundred nm of growth, thus indicating that the GaN films had superior crystallographic quality compared to those grown on sapphire or ZnO/sapphire substrates. Quarter-wafer areas of GaN were removed from the GaN substrate (by selective chemical etching away of the ZnO interlayer). The expensive GaN substrates were then reclaimed/reused (without the need for polishing) for a second cycle of ZnO and GaN growth, which gave similar XRD, SEM, CL and AFM results to the first cycle.

NiO was grown on Si (111), c-Al 2 O 3 and FTO/glass substrates by pulsed laser deposition (PLD). X-Ray Diffraction (XRD) and scanning electron microscope (SEM) studies revealed that layers grown on c-Al 2 O 3 were fcc NiO with a dense morphology of cubic grains that were strongly (111) oriented along the growth direction. The relatively low ω rocking curve linewidth, of 0.12°suggests that there may have been epitaxial growth on the c-Al 2 O 3 substrate. XRD and SEM indicated that films grown on Si (111) were also fcc NiO, with cubic grains, but that the grain orientation was random. This is consistent with the presence of an amorphous SiO 2 layer at the surface of the Si substrate, which precluded epitaxial growth. NiO grown at lower temperature (200°C) on temperature-sensitive FTO/glass substrates showed no evidence of crystallinity in XRD and SEM studies. After flash annealing in air, however, peaks characteristic of randomly oriented fcc NiO appeared in the XRD scans and the surface morphology became more granular in appearance. Such layers appear promising for the development of future dye-sensitised solar cell devices based on NiO grown by PLD.

In situ reflection high-energy electron diffraction (RHEED) is employed to investigate the growth kinetics, and monitor the crystal surface evolution, during plasma-assisted molecular beam epitaxy growth of Bi2Sr2Can−1CunO (BSCCO) compounds. By varying the growth parameters such as operating pressure, substrate temperature, cation flux and shutter opening pulse duration, it is found that the crystal growth front exhibits surface reconstructions with (1×1), (2×2), c(2×2) and (3×1) symmetries for the Sr, Ca and Cu species, and a RHEED pattern characteristic of twinning for Bi. Through manipulation of these surface reconstructions, and use of an adapted growth mode, it was possible to achieve a monolayer coverage for each species supplied. For the n=1, 2 and 3 compounds the resulting films exhibit a crystal quality characterised by an X-ray diffraction rocking curve width of 0.03° and an atomic force microscope mean surface roughness of 0.9 nm [over 10×10 μm] for 40 nm thick films.

The molecular beam epitaxy (MBE) growth of Bi2Sr2Can-1CunOy (BSCCO) and (Sr, Ca)mCunOy `infinite layer' (IL) thin films is reviewed. After introducing the interest in these materials the paper outlines the adaptations necessary to grow cuprate superconductors in an MBE system, isolates six critical parameters for such growths and examines how they are adjusted in order to obtain highly oriented films with elevated TC for various BSCCO and IL phases investigated during the decade in which the subject has been studied. Particular emphasis is given to control of the growth modes and mechanisms for each constituent layer through use of reflection high-energy electron diffraction.

The temperature sensitivity of three egg ages of Plodia interpunctella (Hubner) were examined at 42–48°C heat (hot water) only treatments, 0.5–11.5°C cold storage only treatments, or combination treatments of 42 or 46°C, followed by subsequent 0–10.5°C cold storage. The 1-day-old egg was typically more tolerant of heat only treatments than the 2- and 3-day-old egg. A 99% mortality of all egg ages was achieved in 10.3 hours at 42°C which reduced to 34 minutes at 48°C. This tolerance was reversed at all cold storage temperatures and mortality was achieved quicker at lower temperatures. More than 22 days at ⩾4°C were required to achieve 99% mortality of the most tolerant 3-day-old egg, which was reduced to 19.8 days at 0.5°C for all egg ages. Heat treatments decreased the overall cold storage time required to obtain 99% mortality. Following heat treatment at 42°C, the 2- and 3-day-old eggs were more tolerant to subsequent cold storage than the 1-day-old egg. At 46°C, the 1-day-old was more tolerant to subsequent cold storage regardless of temperature. Eight days at 10.5°C following 6.5 hours at 42°C, or 7.7 minutes at 46°C, resulted in 99.9% mortality of all egg ages. Heat and cold storage may be implemented as part of the manufacturing and storage process of stored products, while also providing a safe and non-chemical method for control of P. interpunctella eggs.

International audience; Stimulated surface- and edge-emissions were investigated for ZnO thin films grown epitaxially by pulsed laser deposition. The lasing threshold was 0.32 MW/cm2 for surface pumping and 0.5 MW/cm2 for edge pumping, which is significantly lower than thresholds observed previously. A modified variable stripe length method was used to measure the gain, which was 1369 cm−1 for the N-band emission. Losses were measured using the shifting excitation spot method and values of 6.2 cm−1 and 6.3 cm−1 were found for the N-band and P-band, respectively. The measured gain and loss were the highest and lowest (respectively) ever reported for ZnO films.

International audience; Zinc oxide (ZnO) epitaxial thin films grown on c-sapphire substrates by pulsed laser deposition were investigated using angle and polarization-resolved photoluminescence spectroscopy. Side-emission spectra differed significantly from surface-emission spectra in exhibiting dominant, narrow, polarization-resolved peaks. These spectral features were attributed to leaky substrate modes in the layers. Observations were first verified using transmission calculations with non-adjustable parameters, which took into account the dispersion, the anisotropy of the ZnO refractive index, and the dependence on film thickness. Results were consistent with Fabry-Perot-like interference being the origin of the distinctive ZnO luminescence observed at grazing incidence angles. A second analysis, based on the source terms method, was used in order to retrieve the bulk emission properties, including the wavelength-dependent quantum yield and the emission anisotropy. While ZnO thin films were considered here, this analysis method can be extended to any luminescent thin film of similar geometry, demonstrating the potential of leaky mode analysis for probing passive and active material properties.

International audience; Zinc oxide thin films were grown on c-sapphire substrates using pulsed laser deposition. Pump power dependence of surface emission spectra, acquired using a quadrupled 266 nm laser, revealed room temperature stimulated emission (threshold of 900 kW/cm2). Time dependent spectral analysis plus gain measurements of single-shot, side-emission spectra pumped with a nitrogen laser revealed random lasing indicative of the presence of self-forming laser cavities. It is suggested that random lasing in an epitaxial system rather than a three-dimensional configuration of disordered scattering elements was due to waveguiding in the film. Waveguiding causes light to be amplified within randomly formed closed-loops acting as lasing cavities.

GaN thin films were grown on ZnO/c-Al 2 O 3 with excellent uniformity over 2 in. diameter wafers using a low temperature/pressure MOVPE process with N 2 as a carrier and dimethylhydrazine as an N source. 5 mm×5 mm sections of similar GaN layers were direct-fusion-bonded onto soda lime glass substrates after chemical lift-off from the sapphire substrates. X-Ray Diffraction, Scanning Electron Microscopy and Transmission Electron Microscopy confirmed the bonding of crack-free wurtzite GaN films onto a glass substrate with a very good quality of interface, i.e. continuous/uniform adherence and absence of voids or particle inclusions. Using this approach, (In) GaN based devices can be lifted-off expensive single crystal substrates and bonded onto supports with a better cost-performance profile. Moreover, the approach offers the possibility of reclaiming the expensive sapphire substrate so it can be utilized again for growth.

MgZnO thin films were grown on c-sapphire and ZnO-coated c-sapphire substrates by pulsed laser deposition from a ZnMgO target with 4 at% Mg. The MgZnO grown on the ZnO underlayer showed significantly better crystal quality than that grown directly on sapphire. AFM studies revealed a significant deterioration in surface morphology for the MgZnO layers compared with the ZnO underlayer. Optical transmission studies indicated a MgZnO bandgap of 3.61eV (compared with 3.34eV for the ZnO), which corresponds to a Mg content of about 16.1 at%. The MgZnO/ZnO heterojunction showed an anomalously low resistivity, which was more than two orders of magnitude less than the MgZnO layer and an order of magnitude lower than that for the ZnO layer. It was suggested that this may be attributable to the presence of a 2D electron gas at the ZnMgO/ZnO heterointerface.

InGaN-based p-i-n structures were transferred from sapphire to soda-lime glass substrates using two approaches: (1) laser-lift-off (LLO) and thermo-metallic bonding and (2) chemical lift-off (LLO) by means sacrificial ZnO templates and direct wafer bonding. Both processes were found to function at RT and allow reclaim of the expensive single crystal substrate. Both approaches have also already been demonstrated to work for the wafer-scale transfer of III/V semiconductors. Compared with the industry-standard LLO, the CLO offers the added advantages of a lattice match to InGaN with higher indium contents, no need for an interfacial adhesive layer (which facilitates electrical, optical and thermal coupling), no damaged/contaminated GaN surface layer, simplified sapphire reclaim (GaN residue after LLO may complicate reclaim) and cost savings linked to elimination of the expensive LLO process.

Indium Gallium Nitride (InGaN) based PV have the best fit to the solar spectrum of any alloy system and emerging LED lighting based on InGaN technology and has the potential to reduce energy consumption by nearly one half while enabling significant carbon emission reduction. However, getting the maximum benefit from GaN diode -based PV and LEDs will require wide-scale adoption. A key bottleneck for this is the device cost, which is currently dominated by the substrate (i.e. sapphire) and the epitaxy (i.e. GaN). This work investigates two schemes for reducing such costs. First, we investigated the integration of Zinc Oxide (ZnO) in InGaN-based diodes. (Successful growth of GaN on ZnO template layers (on sapphire) was illustrated. These templates can then be used as sacrificial release layers for chemical lift-off. Such an approach provides an alternative to laser lift-off for the transfer of GaN to substrates with a superior cost-performance profile, plus an added advantage of reclaiming the expensive single-crystal sapphire. It was also illustrated that substitution of low temperature n-type ZnO for n-GaN layers can combat indium leakage from InGaN quantum well active layers in inverted p-n junction structures. The ZnO overlayers can also double as transparent contacts with a nanostructured surface which enhances light in/out coupling. Thus ZnO was confirmed to be an effective GaN substitute which offers added flexibility in device design and can be used in order to simultaneously reduce the epitaxial cost and boost the device performance. Second, we investigated the use of GaN templates on patterned Silicon (100) substrates for reduced substrate cost LED applications. Controlled local metal organic chemical vapor deposition epitaxy of cubic phase GaN with on-axis Si(100) substrates was illustrated. Scanning electron microscopy and transmission electron microscopy techniques were used to investigate uniformity and examine the defect structure in the GaN. Our results suggest that groove structures are very promising for controlled local epitaxy of cubic phase GaN. Overall, it is concluded that there are significant opportunities for cost reduction in novel hybrid diodes based on ZnOInGaN-Si hybridization.

Due to their combination of good electrical conductivity and optical transparency, Transparent Conducting Oxides (TCOs) are the most common choice as transparent electrodes for optoelectronics applications. In particular, devices, such as LEDs, LCDs, touch screens and solar cells typically employ indium tin oxide. However, indium has some significant drawbacks, including toxicity issues (which are hampering manufacturing), an increasing rarefication (due to a combination of relative scarcity and increasing demand [1]) and resulting price increases. Moreover, there is no satisfactory option at the moment for use as a p-type transparent contact. Thus alternative materials solutions are actively being sought. This review will compare the performance and perspectives of graphene with respect to TCOs for use in transparent conductor applications.