Picosecond time-resolved dynamics of energy transfer between GaN and the various excited states of Eu3+ ions
Picosecond time-resolved dynamics of energy transfer between GaN and the various excited states of Eu3+ ions
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GaN 与 Eu3 离子各种激发态之间能量转移的皮秒时间分辨动力学
DOI：
10.1103/physrevb.100.081201
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发表时间：
2019
影响因子：
3.7
通讯作者：
and V. Dierolf
中科院分区：
文献类型：
--
作者：
R. Wei;B. Mitchell;D. Timmerman;T. Gregorkiewicz;W. Zhu;J. Tatebayashi;S. Ichikawa;Y. Fujiwara;and V. Dierolf
为了阐明最近开发的高效红光发光二极管中使用的Eu掺杂GaN层中的能量转移和再激发过程，进行了一系列系统的光致发光和时间分辨光致发光（TR-PL）测量。利用具有高时间分辨率的TR-PL揭示了“慢”Eu工艺（μs）如何与快半导体工艺（μ ps）竞争的关键见解，因为发现从GaN到离子的初始能量转移在<100 ps的时间尺度上迅速发生。低于带隙共振激发被用来识别的状态，能量转移发生。对于最有效的Eu缺陷复合物，这种转移主要直接发生在的状态。效率较低的复合物也表现出转移到thestate，其发射可以检测到在低温下使用光致发光，表明器件效率的激发途径的重要性。在高激发强度下，也会发生再激发，导致布居数重新分布到、、或态。
To elucidate the energy transfer and reexcitation processes in Eu-doped GaN layers that are used in recently developed, highly efficient red light-emitting diodes, a systematic series of photoluminescence and time-resolved photoluminescence (TR-PL) measurements was performed. Critical insights on how “slow” Eu processes (∼µs) can compete against fast semiconductor processes (∼ps) are revealed using TR-PL with a high temporal resolution, as it is found that the initial energy transfer from GaN to theions takes place rapidly, on a timescale of <100 ps. Below band-gap resonant excitation was used to identify the states into which the energy transfer occurs. For the most efficient Eu defect complexes, this transfer dominantly occurs directly into thestate of. Less efficient complexes also exhibit transfer into thestate, the emission of which can be detected using photoluminescence at low temperature, indicating the importance of the excitation pathway on device efficiency. Under high excitation intensity, reexcitation can also occur, leading to a redistribution of population into the,, orstates.