Browsing by Author "Hong, Yu-Liang"

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Background and Photoexcited Carrier Dependence of Terahertz Radiation from Mg-Doped Nonpolar Indium Nitride Films
(2010)
Ahn, Hyeyoung
;
Yeh, Yi-Jou
;
Hong, Yu-Liang
;
Gwo, Shangjr
;
光電工程學系
We report terahertz (THz) generation from Mg-doped nonpolar (a-plane) InN (a-InN:Mg). While the amplitude and polarity of the THz field from Mg-doped polar (c-plane) InN depend on the background carrier density, the p-polarized THz field from a-InN: Mg has background carrier-insensitive intensity and polarity, which can be attributed to carrier transport in a polarization-induced in-plane electric field. A small but apparent azimuthal angle dependence of the THz field from a-InN:Mg shows the additional contribution of the second-order nonlinear optical effect. Meanwhile, in this study, we did not observe the contribution of the intrinsic in-plane electric field which is significant for high stacking fault density nonpolar InN. (C) 2010 The Japan Society of Applied Physics
Carrier dynamics in InN nanorod arrays
(2012-01-16)
Ahn, Hyeyoung
;
Yu, Chih-Cheng
;
Yu, Pyng
;
Tang, Jau
;
Hong, Yu-Liang
In this report, we investigated ultrafast carrier dynamics of vertically aligned indium nitride (InN) nanorod (NR) arrays grown by molecular-beam epitaxy on Si(111) substrates. Dominant band filling effects were observed and were attributed to a partial bleaching of absorption at the probe wavelengths near the absorption edge. Carrier relaxation in nanorod samples was strongly dependent on the rod size and length. In particular, a fast initial decay was observed for carriers in NRs with a small diameter (similar to 30 nm), the lifetime of which is much shorter than the carrier cooling time, demonstrating the substantial surface-associated influence on carrier relaxation in semiconductor nanostructures. (C)2012 Optical Society of America