1 research outputs found
Axial Inhomogeneity of Mg-Doped GaN Rods: A Strong Correlation among Componential, Electrical, and Optical Analyses
We systematically characterized the
inhomogeneous doping properties
along the <i>c</i>-axis of Mg-doped <i>p</i>-GaN
microrods. Axial variation of doping concentration and electrical
resistance on the <i>p</i>-GaN rod were measured by time-of-flight
secondary-ion-mass-spectrometry and four-point probe measurements,
respectively. Defects-related optical information was obtained from
photoluminescence spectra together with Raman experiments revealing
the change of crystal quality and strain along the rod. On the basis
of a correlation of these analyses, we confirmed that Mg concentration
decreased along the axial direction of the rod, leading to increasing
electrical resistance. This axial Mg concentration change was revealed
by green luminescence because the intensity of green luminescence
sensitively varied with the doping density in both high-doping and
low-doping rods. Interestingly, all the resistances at the highly
doped rods were higher than the lowly doped rods due to overall mobility
degradation at the high-doping rods caused by a scattering effect
of increased Mg impurities and strain. All analyses provided complementary
information on the <i>p</i>-type doping process and contribute
to understanding the <i>p</i>-doping properties of GaN rod
based photonic devices. Furthermore, our axially resolved optical
spectroscopic (photoluminescence and Raman) methods can provide a
facile, fast, and nondestructive way to estimate the axial doping
and conductivity inhomogeneity of a Mg-doped <i>p</i>-GaN
rod without having complex, time-consuming, and destructive structural
and electrical measurements