No abstract

We report the development of 480 nm cyan and 520 nm green light emitting diodes (LEDs) with a highly stable emission wavelength. The shift is less than 3 nm when the drive current density is changed from 0.1 to 38 A/cm2. LEDs have been obtained in GaInN-based homoepitaxy on nonpolar m-plane GaN bulk substrates. For increasing emission wavelength we find a large number of additional dislocations generated within the quantum wells (2×108 to ∼1010 cm2) and a decrease in the electroluminescence efficiency. This suggests that the strain induced generation of defects plays a significant role in the performance limitations.

Improved quantum efficiency and short radiative lifetime were demonstrated for the near-band-edge emission of nearly stacking-fault-free, 200–250-nm-thick, m-plane pseudomorphic InxGa1−xN (0<x≤0.14) films grown by metalorganic vapor phase epitaxy on the low threading dislocation density (<5×106 cm−2) freestanding (FS) GaN substrates. Values of full width at half maximum of x-ray ω-rocking curves of the InxGa1−xN films remain unchanged as the substrate values being 80 and 60 arcsec for the (101¯0) diffraction with ⟨0001⟩ and ⟨112¯0⟩ azimuths, respectively, and 80 arcsec for the (101¯2) diffraction. As the surface flatness was improved, the incorporation efficiency of In was lower than the cases for c-plane growth and m-plane growth on a defective GaN substrate, according to nonidentical surface kinetics and absence of inclined/tilted planes, respectively.

The study looks at the effects of the Medicaid expansion on health outcomes, healthcare utilization and access to healthcare through the Center of Disease Control's Behavioral Risk Factor Surveillance System. In particular, we looked into whether Medicaid Expansion has caused an increase in healthcare access, healthcare utilization, and positive health outcomes among newly insured Medicaid patients. We applied the difference‐in difference models to cholesterol check, health plan, and medical cost. Our results indicated evidence a positive effect associated with state Medicaid expansions for adults and the utilization of preventive care increased in expansion states after the Medicaid expansion as more Medicaid recipients received blood pressure checks and regular primary care checkups relative to the nonexpansion states.