In-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching
In-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching
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DOI：
10.1063/1.1465123
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发表时间：
2002-05-01
影响因子：
3.2
通讯作者：
Bohn, PW
中科院分区：
文献类型：
--
作者：
Chattopadhyay, S;Li, XL;Bohn, PW
在1:2:1的HF、H2O2和甲醇溶液中，采用pt辅助化学刻蚀法制备了p(-)- si（100）光致发光多孔硅（PSi）。通过改变刻蚀时间，PSi的峰值发射波长可以在500 nm以下或等于600 nm的范围内调谐。这种发光在所有波长上都足够强烈，肉眼可见。此外，通过在蚀刻之前对表面上的金属区域进行图案化，可以在空间上控制发光。为了研究加工变量（主要是蚀刻时间和与Pt的空间接近度）与形貌之间的关系，进行了扫描电子显微镜（SEM），真彩色荧光显微镜和空间分辨声子线形状的研究。扫描电镜图像显示发光起源区域的纳米晶体特征，该区域作为蚀刻时间的函数在空间上移动，如荧光显微镜所示。在声子约束模型的背景下，纵向光学声子带的位移和展宽的拉曼散射测量被用来估计晶体的大小。与发光一样，发现晶体尺寸随与Pt图案区域的距离和蚀刻时间的变化而变化。这些结果是根据一种蚀刻机制来解释的，其中H2O2还原导致价带深处的空穴注入，然后在空间上漂移，并在决定Si从表面去除的速率中起关键作用。(C) 2002年美国物理研究所。
Photoluminescent porous silicon (PSi) was produced by Pt-assisted electroless etching of p(-)-Si (100) in a 1:2:1 solution of HF, H2O2, and methanol. The peak emission wavelength of the PSi could be tuned in the range 500 nmless than or equal tolambdaless than or equal to600 nm simply by changing the time of etching. The luminescence is sufficiently intense at all wavelengths to be visible by eye. Furthermore, by patterning the metal areas on the surface prior to etching, the luminescence can be controlled spatially. To investigate the relationship among processing variables - principally etch time and spatial proximity to Pt - and morphology, scanning electron microscopy (SEM), true color fluorescence microscopy, and spatially resolved phonon line shape studies were undertaken. SEM images show nanocrystalline features in the region where the luminescence originates, a region which shifts spatially as a function of etch time, as indicated by fluorescence microscopy. Raman scattering measurements of the shift and broadening of the longitudinal optical phonon band interpreted in the context of the phonon confinement model were used to estimate crystallite sizes. As with the luminescence, the crystallite sizes were found to vary as a function of distance from the Pt patterned area and etch time. These results are interpreted in light of an etching mechanism in which H2O2 reduction results in hole injection deep into the valence band, which then drifts spatially and plays a critical role in determining the rate at which Si is removed from the surface. (C) 2002 American Institute of Physics.