tailieunhanh - Báo cáo hóa học: " Cathodoluminescence spectra of gallium nitride nanorods"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Cathodoluminescence spectra of gallium nitride nanorods | Tsai et al. Nanoscale Research Letters 2011 6 631 http content 6 1 631 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Cathodoluminescence spectra of gallium nitride nanorods Z-I Z-I-I- I 1 1 1 1 1 Chia-Chang Tsai Guan-Hua Li Yuan-Ting Lin Ching-Wen Chang Paritosh Wadekar Quark Yung-Sung Chen Lorenzo Rigutti2 Maria Tchernycheva2 Frangois Henri Julien2 and Li-Wei Tu1 Abstract Gallium nitride GaN nanorods grown on a Si 111 substrate at 720 C via plasma-assisted molecular beam epitaxy were studied by field-emission electron microscopy and cathodoluminescence CL . The surface topography and optical properties of the GaN nanorod cluster and single GaN nanorod were measured and discussed. The defect-related CL spectra of GaN nanorods and their dependence on temperature were investigated. The CL spectra along the length of the individual GaN nanorod were also studied. The results reveal that the peak comes from the structural defect at the interface between the GaN nanorod and Si substrate. The surface state emission of the single GaN nanorod is stronger as the diameter of the GaN nanorod becomes smaller due to an increased surface-to-volume ratio. Keywords gallium nitride nanorod cathodoluminescence scanning electron microscopy Introduction Recently the applications of semiconductor materials in optoelectronic devices grow rapidly. Among them due to the high thermal conductivity wide direct bandgap and chemical stability III-V family nitride-based semiconductors including aluminum nitride AlN gallium nitride GaN and indium nitride InN and their alloys have attracted lots of studies in the applications on light-emitting diodes and laser diodes. The bandgaps for AIN GaN and InN are eV eV and eV respectively. By varying the composition of these three nitride-based materials the emission light energy will range from eV to eV 1 . Through the studies of the fundamental properties of the .