Now showing items 1-11 of 11

    • Energy-saving quality road lighting with colloidal quantum dot nanophosphors 

      Erdem, T.; Kelestemur, Y.; Soran-Erdem, Z.; Ji, Y.; Demir, Hilmi Volkan (Walter de Gruyter GmbH, 2014)
      Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, ...
    • A hole accelerator for InGaN/GaN light-emitting diodes 

      Zhang, Z. H.; Liu, W.; Tan, S. T.; Ji, Y.; Wang, L.; Zhu, B.; Zhang, Y.; Lu, S.; Zhang, X.; Hasanov, N.; Sun, X. W.; Demir, Hilmi Volkan (AIP Publishing, 2014)
      The quantum efficiency of InGaN/GaN light-emitting diodes (LEDs) has been significantly limited by the insufficient hole injection, and this is caused by the inefficient p-type doping and the low hole mobility. The low ...
    • Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers 

      Ju, Z. G.; Liu, W.; Zhang, Z. H.; Tan, S. T.; Ji, Y.; Kyaw, Z. B.; Zhang, X. L.; Lu, S. P.; Zhang, Y. P.; Zhu, B.; Hasanov, N.; Sun, X. W.; Demir, Hilmi Volkan (AIP Publishing, 2013)
      InGaN/GaN light-emitting diodes (LEDs) with graded-thickness quantum barriers (GTQB) are designed and grown by metal-organic chemical-vapor deposition. The proposed GTQB structure, in which the barrier thickness decreases ...
    • Improved InGaN/GaN light-emitting diodes with a p-GaN/n-GaN/p-GaN/n-GaN/p-GaN current-spreading layer 

      Zhang, Z.-H.; Tan, S.T.; Liu W.; Ju, Z.; Zheng, K.; Kyaw, Z.; Ji, Y.; Hasanov, N.; Sun X.W.; Demir, Hilmi Volkan (Optical Society of American (OSA), 2013)
      This work reports both experimental and theoretical studies on the InGaN/GaN light-emitting diodes (LEDs) with optical output power and external quantum efficiency (EQE) levels substantially enhanced by incorporating ...
    • Low thermal-mass LEDs: Size effect and limits 

      Lu, S.; Liu W.; Zhang, Z.-H.; Tan, S.T.; Ju, Z.; Ji, Y.; Zhang X.; Zhang, Y.; Zhu, B.; Kyaw, Z.; Hasanov, N.; Sun X.W.; Demir, Hilmi Volkan (Optical Society of American (OSA), 2014)
      In this work, low thermal-mass LEDs (LTM-LEDs) were developed and demonstrated in flip-chip configuration, studying both experimentally and theoretically the enhanced electrical and optical characteristics and the limits. ...
    • Nonradiative recombination-Critical in choosing quantum well number for InGaN/GaN light-emitting diodes 

      Zhang, Y.P.; Zhang, Z.-H.; Liu W.; Tan, S.T.; Ju, Z.G.; Zhang X.L.; Ji, Y.; Wang L.C.; Kyaw, Z.; Hasanov, N.; Zhu, B.B.; Lu, S.P.; Sun X.W.; Demir, Hilmi Volkan (Optical Society of American (OSA), 2015)
      In this work, InGaN/GaN light-emitting diodes (LEDs) possessing varied quantum well (QW) numbers were systematically investigated both numerically and experimentally. The numerical computations show that with the increased ...
    • On the effect of N-GaN/P-GaN/N-GaN/P-GaN/N-GaN built-in junctions in the n-GaN layer for InGaN/GaN light-emitting diodes 

      Kyaw, Z.; Zhang, Z. H.; Liu, W.; Tan, S. T.; Ju, Z. G.; Zhang, X. L.; Ji, Y.; Hasanov, N.; Zhu, B.; Lu, S.; Zhang, Y.; Sun, X. W.; Demir, Hilmi Volkan (Optical Society of America, 2014-01-07)
      N-GaN/P-GaN/N-GaN/P-GaN/N-GaN (NPNPN-GaN) junctions embedded between the n-GaN region and multiple quantum wells (MQWs) are systematically studied both experimentally and theoretically to increase the performance of InGaN/GaN ...
    • On the mechanisms of InGaN electron cooler in InGaN/GaN light-emitting diodes 

      Zhang, Z. H.; W. L.; Tan, S. T.; Ju, Z.; Ji, Y.; Kyaw, Z.; Zhang, X.; Hasanov, N.; Zhu, B.; Lu, S.; Zhang, Y.; Sun, X. W.; Demir, Hilmi Volkan (Optical Society of America, 2014)
      Electron overflow limits the quantum efficiency of InGaN/GaN light-emitting diodes. InGaN electron cooler (EC) can be inserted before growing InGaN/GaN multiple quantum wells (MQWs) to reduce electron overflow. However, ...
    • P-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas 

      Zhang, Z.-H.; Tiam Tan, S.; Kyaw, Z.; Liu W.; Ji, Y.; Ju, Z.; Zhang X.; Wei Sun X.; Volkan Demir H. (2013)
      Here, GaN/AlxGa1-xN heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional ...
    • A PN-type quantum barrier for InGaN/GaN light emitting diodes 

      Zhang, Z.-H.; Tan, S.T.; Ji, Y.; Liu W.; Ju, Z.; Kyaw, Z.; Sun X.W.; Demir, Hilmi Volkan (Optical Society of American (OSA), 2013)
      In this work, InGaN/GaN light-emitting diodes (LEDs) with PN-type quantum barriers are comparatively studied both theoretically and experimentally. A strong enhancement in the optical output power is obtained from the ...
    • Room-temperature larger-scale highly ordered nanorod imprints of ZnO film 

      Kyaw, Z.; Wang J.; Dev, K.; Tiam Tan, S.; Ju, Z.; Zhang, Z.-H.; Ji, Y.; Hasanov, N.; Liu W.; Sun X.W.; Demir, Hilmi Volkan (Optical Society of American (OSA), 2013)
      Room-temperature large-scale highly ordered nanorod-patterned ZnO films directly integrated on III-nitride light-emitting diodes (LEDs) are proposed and demonstrated via low-cost modified nanoimprinting, avoiding a ...