Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (2 results)

  • Article
Lawrence Berkeley National Laboratory (2004)

GaN/InGaN light emitting diodes (LEDs) are commercialized for lighting applications because of the cost efficient way that they produce light of high brightness1,2. Nevertheless, there is significant room for improving their external emission efficiency3 from typical values below 10 percent4 to more than 50 percent5, which are obtainable by use of other materials systems that, however, do not cover the visible spectrum. In particular, green-light emitting diodes fall short in this respect1-3, which is troublesome since the human eye is most sensitive in this spectral range. In this letter advanced electron microscopy is used to characterize indium segregation in InGaN quantum wells of high-brightness, green LEDs (with external quantum efficiency as high as 15 percent at 75 A/cm2). Our investigations reveal the presence of 1-3 nm wide indium rich clusters in these devices with indium concentrations as large as 0.30-0.40 that narrow the band gap locally to energies as small as 2.65 eV.

    Cover page: Local indium segregation and band structure in high efficiency green light emitting InGaN/GaN diodes
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2012)
    Abstract Abstract 1111 Collapse of membrane lipid asymmetry is a hallmark of blood coagulation. TMEM16F of the TMEM16 family that includes TMEM16A/B Ca2+-activated Cl− channels (CaCCs) is linked to Scott Syndrome with deficient Ca2+-dependent lipid scrambling. We generated TMEM16F-knockout mice that exhibit bleeding defects associated with platelet deficiency in Ca2+-dependent phosphatidylserine exposure and procoagulant activity, and lack a Ca2+-activated cation current in the platelet precursor megakaryocytes. TMEM16F channels permeate both monovalent and divalent cations including Ca2+, and exhibit synergistic gating by Ca2+ and voltage. We further pinpointed a residue in the putative pore region important for the cation versus anion selectivity of TMEM16F-SCAN and TMEM16A-CaCC channels. This study thus identifies a novel Ca2+-activated channel permeable to Ca2+ and critical for Ca2+-dependent scramblase activity. Disclosures: No relevant conflicts of interest to declare.
      Top