A graded-composition electron blocking layer (GEBL) with aluminum composition increasing along the [0001] direction was designed for c-plane InGaN/GaN light-emitting diodes (LEDs) by employing the band-engineering. The simulation results demonstrated that such GEBL can effectively enhance the capability of hole transportation across the EBL as well as the electron confinement. Consequently, the LED with GEBL grown by metal-organic chemical vapor deposition exhibited lower forward voltage and series resistance and much higher output power at high current density as compared to conventional LED. Meanwhile, the efficiency droop was reduced from 34% in conventional LED to only 4% from the maximum value at low injection current to 200 A/cm2.

Erbium-doped silicon nanowires have been grown via a vapor transport and condensation method with ErCl3∙6H2O powder as part of the source in one step. The Er-doped silicon nanowires exhibit the room temperature photoluminescence at a wavelength of 1.54μm, ideal for optical communication. From I-V measurements, the resistivity of 4.2at.% Er-doped Si nanowires was determined to be 1.5×10−2Ωcm. The Er-doped silicon nanowires were found to possess excellent field emission properties with a field enhancement factor as high as 1260. The rich variety of enhanced physical properties exhibited by the Er-doped silicon nanowires points to versatile applications for advanced devices.