Browsing by Author "Lee, H. -M."

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Influence of structural anisotropy to anisotropic electron mobility in a-plane InN
(2013-02-11)
Ahn, H.
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Chia, J. -W.
;
Lee, H. -M.
;
Gwo, S.
;
光電工程學系
This study reports on the anisotropic electron transport properties and a correlation between the electron mobility (mu) and the stacking faults (SFs) in the a-plane InN film. Electron mobilities measured by terahertz time-domain spectroscopy and Hall effect measurement along the in-plane [(1) over bar 100] (c(perpendicular to)) orientation were much higher than those of the in-plane [0001] (c(parallel to)) orientation. This result shows a sharp contrast to higher defect density for the c(perpendicular to) orientation as measured by x-ray diffraction. The electrons transporting through the planar SFs aligned along the c(perpendicular to) direction are expected to experience more scattering by defects, resulting in lower mu for the c(parallel to) orientation. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792209]
Mg-induced terahertz transparency of indium nitride films
(2011-12-05)
Ahn, H.
;
Chia, J. -W.
;
Lee, H. -M.
;
Hong, Y. -L.
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Gwo, S.
Terahertz time-domain spectroscopy (THz-TDS) has been used to investigate electrical properties of Mg-doped indium nitride (InN). Mg-doping in InN was found to significantly increase terahertz transmittance. THz-TDS analysis based on the Drude model shows that this high transmittance from Mg-doped InN is mainly due to the reduction in mobility associated with ionized dopants. The Hall-effect-measured mobility is typically lower than the THz-TDS-measured mobility for the same samples. However, the results of both measurements have the same slope in the linear relation between mobility and density. By introducing a compensation ratio of similar to 0.2, an excellent agreement in mobilities of two methods is obtained. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3669538]