We report on site-controlled growth of InP/GaInP quantum dots (QDs) on GaAs substrates. The QD nucleation sites are defined by shallow nanoholes etched into a GaInP layer. Optimized growth conditions allow us to realize QD arrays with excellent long range ordering on nanohole periods as large as 1.25 µm. Single QD lines with an average linewidth of 553 µeV and best values below 200 µeV are observed. Photoluminescence spectroscopy reveals excitonic and biexcitonic emission in the wavelength range of about 670 nm (1.85 eV) with an exciton-biexciton splitting of 1.8 meV. Second-order photon-autocorrelation measurements show clear single photon emission with g(2)(0) = 0.13 ± 0.01.

A technology platform for the epitaxial growth of site-controlled InP quantum dots (QDs) on GaAs substrates is presented. Nanoholes are patterned in a GaInP layer on a GaAs substrate by electron beam lithography and dry chemical etching, serving as QD nucleation centers. The effects of a thermal treatment on the structured surfaces for deoxidation are investigated in detail. By regrowth on these surfaces, accurate QD positioning is obtained for square array arrangements with lattice periods of 1.25 μm along with a high suppression of interstitial island formation. The optical properties of these red-emitting QDs (λ ~ 670 nm) are investigated by means of ensemble- and micro-photoluminescence spectroscopy at cryogenic temperatures.

BACKGROUND Assessment of blood consumption (ABC), shock index (SI), and Revised Trauma Score (RTS) are used to estimate the need for blood transfusion and triage. We compared Bleeding Risk Index (BRI) score calculated with trauma patient noninvasive vital signs and hypothesized that prehospital BRI has better performance compared with ABC, RTS, and SI for predicting the need for emergent and massive transfusion (MT). METHODS We analyzed 2-year in-flight data from adult trauma patients transported directly to a Level I trauma center via helicopter. The BRI scores 0 to 1 were derived from continuous features of photoplethymographic and electrocardiographic waveforms, oximetry values, blood pressure trends. The ABC, RTS, and SI were calculated using admission data. The area under the receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) was calculated for predictions of critical administration threshold (CAT, ≥3 units of blood in the first hour) or MT (≥10 units of blood in the first 24 hours). DeLong’s method was used to compare AUROCs for different scoring systems. p < 0.05 was considered statistically significant. RESULTS Among 1,396 patients, age was 46.5 ± 20.1 years (SD), 67.1% were male. The MT rate was 3.2% and CAT was 7.6%, most (92.8%) were blunt injury. Mortality was 6.6%. Scene arrival to hospital time was 35.3 ± (10.5) minutes. The BRI prediction of MT with AUROC 0.92 (95% CI, 0.89–0.95) was significantly better than ABC, SI, or RTS (AUROCs = 0.80, 0.83, 0.78, respectively; 95% CIs 0.73–0.87, 0.76–0.90, 0.71–0.85, respectively). The BRI prediction of CAT had an AUROC of 0.91 (95% CI, 0.86–0.94), which was significantly better than ABC (AUROC, 077; 95% CI, 0.73–0.82) or RTS (AUROC, 0.79; 95% CI, 0.74–0.83) and better than SI (AUROC, 0.85; 95% CI, 0.80–0.89). The BRI score threshold for optimal prediction of CAT was 0.25 and for MT was 0.28. CONCLUSION The autonomous continuous noninvasive patient vital signs–based BRI score performs better than ABC, RTS, and SI predictions of MT and CAT. Bleeding Risk Index does not require additional data entry or expert interpretation. LEVEL OF EVIDENCE Prognostic test, level III.