Nikhil R. Taskar

GaN (0001)-(1×1) surfaces: Composition and electronic properties

We use low energy electron diffraction, Auger electron spectroscopy, and ultraviolet and x-ray photoemission spectroscopy to study the surface structure, stoichiometry, and electronic properties of n- and p-type GaN (0001) grown by metal-organic chemical vapor deposition. Ordered (1×1) surfaces with nearly stoichiometric composition are prepared by nitrogen sputtering and annealing. The band bending is found to be 0.75±0.1 eV up and 0.75±0.1 eV down for n- and p-type samples, respectively. The work function, electron affinity, and Ga 3d core level binding energy are also determined.

Novel technique for p‐type nitrogen doped ZnSe epitaxial layers

We report a novel technique to obtain p‐type ZnSe layers doped with nitrogen. The layers were grown in a low‐pressure metalorganic vapor phase epitaxy system using ammonia as the dopant source. A rapid thermal anneal was used to enhance the activation of the nitrogen acceptors. Net acceptor concentration values as high as 3×1016/cm3 were obtained from capacitance‐voltage measurements and the profile was uniform over the thickness of the epitaxial layers. The 7 K photoluminescence spectrum was dominated by the acceptor bound exciton peak; the donor‐acceptor pair spectra were also observed.