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arXiv 1707.01558cond-mat.mtrl-sciquant-ph
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4 H- SiC中缺陷电荷态的光开关

Optical switching of defect charge states in 4H-SiC

D. Andrew Golter, Chih Wei Lai

摘要:

我们展示了4 H-SiC中明亮和黑暗的带电双空位缺陷之间的光致开关。光致发光激发和时间分辨光致发光测量揭示了这种电荷转换的激发条件。对于低于~ 1.3eV(高于~950 nm)的能量,PL被抑制超过两个数量级。在存在较高能量的再泵激光的情况下,PL被恢复,其时间平均强度小于激发场的0.1%。在2.33 eV(532 nm)的再泵浦下,PL迅速增加,时间常数约为30 $μ$ s。相比之下,当再泵关闭时,PL首先在约100-200 $μ$ s内下降,然后是几秒的慢得多的衰减。我们将这些效应归因于两种不同电荷状态之间的转换。在低于1.3eV的能级的激发下,V $_{Si}$ V $_C$ $^0$被转换成暗电荷状态。能量高于1.3eV的再泵浦激光可以激发该带电态并恢复明亮的中性态。这种光诱导电荷转换会导致电荷状态波动,但可以用于长期数据存储或基于核自旋的量子存储器。

英文摘要:

We demonstrate optically induced switching between bright and dark charged divacancy defects in 4H-SiC. Photoluminescence excitation and time-resolved photoluminescence measurements reveal the excitation conditions for such charge conversion. For an energy below ~1.3 eV (above ~950 nm), the PL is suppressed by more than two orders of magnitude. The PL is recovered in the presence of a higher energy repump laser with a time-averaged intensity less than 0.1% that of the excitation field. Under a repump of 2.33 eV (532 nm), the PL increases rapidly, with a time constant ~30 $μ$s. By contrast, when the repump is switched off, the PL decreases first within ~100-200 $μ$s, followed by a much slower decay of a few seconds. We attribute these effects to the conversion between two different charge states. Under an excitation at energy levels below 1.3 eV, V$_{Si}$V$_C$$^0$ are converted into a dark charge state. A repump laser with an energy above 1.3 eV can excite this charged state and recover the bright neutral state. This optically induced charge switching can lead to charge-state fluctuations but can be exploited for long-term data storage or nuclear-spin-based quantum memory.

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