White light-emitting diodes(LEDs)are becoming an alternative general light source,with huge energy savings compared to conventional lighting.However,white LEDs using phosphor(s)suffer from unavoidable Stokes energy co...White light-emitting diodes(LEDs)are becoming an alternative general light source,with huge energy savings compared to conventional lighting.However,white LEDs using phosphor(s)suffer from unavoidable Stokes energy converting losses,higher manufacturing cost,and reduced thermal stability.Here,we demonstrate electrically driven,phosphor-free,white LEDs based on three-dimensional gallium nitride structures with double concentric truncated hexagonal pyramids.The electroluminescence spectra are stable with varying current.The origin of the emission wavelength is studied by cathodoluminescence and high-angle annular dark field scanning transmission electron microscopy experiments.Spatial variation of the carrier injection efficiency is also investigated by a comparative analysis between spatially resolved photoluminescence and electroluminescence.展开更多
基金supported by the National Research Foundation(NRF-2013R1A2A1A01016914,NRF-2013R1A1A2011750)the Ministry of Education,the Industrial Strategic Technology Development Program(10041878)+1 种基金the Ministry of Knowledge Economy,the Climate Change Research Hub of KAIST(Grant No.N01150041)the GRC project of KAIST Institute for the NanoCentury.
文摘White light-emitting diodes(LEDs)are becoming an alternative general light source,with huge energy savings compared to conventional lighting.However,white LEDs using phosphor(s)suffer from unavoidable Stokes energy converting losses,higher manufacturing cost,and reduced thermal stability.Here,we demonstrate electrically driven,phosphor-free,white LEDs based on three-dimensional gallium nitride structures with double concentric truncated hexagonal pyramids.The electroluminescence spectra are stable with varying current.The origin of the emission wavelength is studied by cathodoluminescence and high-angle annular dark field scanning transmission electron microscopy experiments.Spatial variation of the carrier injection efficiency is also investigated by a comparative analysis between spatially resolved photoluminescence and electroluminescence.
