Crack-free and conductive Si-doped AlN/GaN distributed Bragg reflectors grown on 6H-SiC(0001)

We demonstrate Si-doped n-type AlN/GaN distributed Bragg reflectors grown on 6H-SiC(0001). The structures are crack-free and have a stopband centered around 450 nm with a full width at half maximum between 40 and 50 nm. The maximum measured reflectance is greater than or equal to99%. A comparison between Si-doped and undoped structures reveals no degradation of the reflectance due to the Si doping. Vertical conductance measurements at room temperature on the samples show an ohmic I-V behavior in the entire measurement range. The measured resistivity at 77 K is only a factor of 2 larger than the resistivity measured at room temperature. (C) 2004 American Institute of Physics.