Persistent hole burning in semiconductor nanocrystals
Persistent hole burning in semiconductor nanocrystals
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DOI：
10.1016/0022-2313(96)00073-7
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发表时间：
1996-01-01
影响因子：
3.6
通讯作者：
Masumoto, Y
中科院分区：
文献类型：
--
作者：
Masumoto, Y
在镶嵌于晶体、玻璃或聚合物中的纳米半导体材料如CdSe、CdS、CuCl、CuBr和CuI中发现了持续光谱烧孔（PSHB）现象。在这些纳米晶体的非均匀加宽的激子吸收光谱中，光谱空穴及其相关结构是由窄带激光激发产生的，并且在2K下保存了几个小时以上。孔深与燃烧注量的对数成正比增长。观察到热退火和光致空穴填充现象，烧孔是通过势垒高度和厚度分布较宽的势垒隧穿过程发生的。还观察到与PSHB现象相关的异常发光行为。在发光光谱中表现为随曝光量增加的发光伸长和烧孔现象。所观察到的PSHB现象解释的激子本地化和随后的电离的纳米晶体。光致电离载流子的能量从原始能量中释放出来，新的能量取决于被俘获载流子的空间排列。载流子的量子限制以及由此产生的被限制载流子和被俘获载流子之间的强库仑相互作用对于能量变化是必不可少的。PSHB现象的可能应用进行了讨论。
The persistent spectral hole burning (PSHB) phenomenon was found to occur in many kinds of nanocrystalline semiconductors, such as CdSe, CdS, CuCl, CuBr and CuI, embedded in crystals, glass or polymers. In inhomogeneously broadened exciton absorption spectra of these nanocrystals, the spectral hole and its associated structure were created by the narrow-band laser excitation and were conserved for more than several hours at 2 K. Hole depth grew in proportion to the logarithm of the burning fluence. Thermally-annealing and light-induced hole-filling phenomena were observed, The hole burning takes place by the tunneling process through potential barriers with broadly distributed barrier height and thickness. Unusual luminescence behaviors related to the PSHB phenomena were also observed. They are luminescence elongation with increase of the light exposure and hole burning in the luminescence spectrum. The observed PSHB phenomena are explained by the exciton localization and the succeeding ionization of nanocrystals. The energy of the photoionized nanocrystal is released from the original energy and the new energies depend on the spatial arrangement of the trapped carriers. Quantum confinement of carriers and resulting strong Coulomb interaction between confined carriers and trapped carriers are essential for the energy change. Possible applications of the PSHB phenomenon is discussed.