Field-effect mobility in quantized accumulation layers on ZnO surfaces
Field-effect mobility in quantized accumulation layers on ZnO surfaces
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ZnO 表面量子化累积层的场效应迁移率
DOI：
10.1103/physrevb.19.4107
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发表时间：
1979
影响因子：
3.7
通讯作者：
Y. Goldstein
中科院分区：
文献类型：
--
作者：
M. Nitzan;Y. Grinshpan;Y. Goldstein
本文报道了ZnO晶体极性表面强积累层的场效应迁移率${\ensuremath{\mu}}_{\mathrm{FE}}$的测量结果。结果表明${\ensuremath{\mu}}_{\mathrm{FE}}$是表面电子密度$\ensuremath{\Delta}N$（在${10}^{12}$ - ${10}^{14}$${\mathrm{cm}}^{\ensuremath{-}2}$范围内）和温度（2-300 K）的函数。通过适当的积分程序，可以从场效应数据中推导出普通电导率迁移率$\ensuremath{\mu}$作为$\ensuremath{\Delta}N$和温度的函数。在一定温度下，${\ensuremath{\mu}}_{\mathrm{FE}}$和$\ensuremath{\mu}$均先随$\ensuremath{\Delta}N$的增加而升高，在$\ensuremath{\Delta}N\ensuremath{\approx}(2\ensuremath{-}5)\ifmmode\times\else\texttimes\fi{}{10}^{13}$${\mathrm{cm}}^{\ensuremath{-}2}$达到最大值，然后随$\ensuremath{\Delta}N$的进一步增加而逐渐降低。对于高温$\ensuremath{\Delta}N$ (\ensuremath{\gtrsim}${10}^{13}$${\mathrm{cm}}^{\ensuremath{-}2}$) ${\ensuremath{\mu}}_{\mathrm{FE}}$和$\ensuremath{\mu}$实际上与温度无关；对于低温$\ensuremath{\Delta}N$ (\ensuremath{\lesssim} 3 \ifmmode\times\else\texttimes\fi{}${10}^{12}$)，它们随着温度的降低而强烈降低，表明在低温下载流子局部化。电导率迁移率$\ensuremath{\mu}$的结果与之前报道的霍尔迁移率${\ensuremath{\mu}}_{H}$的结果很好地吻合，并进一步支持了其中提出的由表面离子大团簇组成的带电散射中心模型。
Measurements are reported of the field-effect mobility ${\ensuremath{\mu}}_{\mathrm{FE}}$ in strong accumulation layers on the polar surfaces of ZnO crystals. Results are presented of ${\ensuremath{\mu}}_{\mathrm{FE}}$ as a function of surface electron density $\ensuremath{\Delta}N$ (in the range ${10}^{12}$-${10}^{14}$ ${\mathrm{cm}}^{\ensuremath{-}2}$) and of temperature (2-300 K). By a suitable integration procedure it has been possible to derive from the field-effect data the ordinary conductivity mobility $\ensuremath{\mu}$ as a function of $\ensuremath{\Delta}N$ and temperature. At a fixed temperature both ${\ensuremath{\mu}}_{\mathrm{FE}}$ and $\ensuremath{\mu}$ initially rise with increasing $\ensuremath{\Delta}N$, reach a maximum at $\ensuremath{\Delta}N\ensuremath{\approx}(2\ensuremath{-}5)\ifmmode\times\else\texttimes\fi{}{10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}2}$, and then gradually decrease with a further increase in $\ensuremath{\Delta}N$. For high $\ensuremath{\Delta}N$ (\ensuremath{\gtrsim} ${10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}2}$) ${\ensuremath{\mu}}_{\mathrm{FE}}$ and $\ensuremath{\mu}$ are practically temperature independent; for low $\ensuremath{\Delta}N$ (\ensuremath{\lesssim} 3 \ifmmode\times\else\texttimes\fi{} ${10}^{12}$) they decrease strongly with decreasing temperature, indicating carrier localization at low temperatures. The results of the conductivity mobility $\ensuremath{\mu}$ agree well with those of the Hall mobility ${\ensuremath{\mu}}_{H}$ reported earlier, and provide further support for the model proposed there of charged scattering centers consisting of large conglomerates of surface ions.