Spectroscopic and energy transfer studies of Eu3+ centers in GaN
Spectroscopic and energy transfer studies of Eu3+ centers in GaN
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DOI：
10.1063/1.2783893
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发表时间：
2007-10-01
影响因子：
3.2
通讯作者：
Steckl, Andrew J.
中科院分区：
文献类型：
--
作者：
Peng, Hongying;Lee, Chang-Won;Steckl, Andrew J.
用常规固体源分子束外延(MBE)和间断生长分子束外延(MBE)生长了掺Eu GaN薄膜，在室温和86K下进行了光致发光(PL)、光致发光激发(PLE)和时间分辨光致发光光谱研究。在1.8-2.7 eV的可见光谱范围内，观察到42个光谱特征，并尝试对每个跃迁进行指认。PL和PLE表明，GaN晶格中存在4个Eu3+中心，其相对浓度可以通过生长中断的时间来控制。这四个位置的能级是自洽获得的，时间分辨光致发光测量揭示了这些能级之间的辐射和非辐射弛豫的细节。数据表明，这些位置之间存在近乎共振的交叉弛豫。通过在D-5(0)态中分别填充2.4和2.8亩S的特征时间，观察到D-5(2)和D-5(1)态的非辐射衰变。发现D-5(0)态的驰豫方式与终态和掺杂位置略有关系。(C)2007年美国物理研究所。
Photoluminescence (PL), photoluminescence excitation (PLE), and time-resolved PL spectroscopies have been carried out at room temperature and 86 K on transitions from D-5(2), D-5(1), and D-5(0) excited states to numerous F-7(J) ground states of Eu-doped GaN films grown by conventional solid-source molecular beam epitaxy (MBE) and interrupted growth epitaxy MBE. Within the visible spectral range of 1.8-2.7 eV, 42 spectral features were observed and assignments were attempted for each transition. PL and PLE indicate that four Eu3+ centers exist in the GaN lattice whose relative concentration can be controlled by the duration of growth interruption. The energy levels for these four sites are self-consistently obtained, and time-resolved photoluminescence measurements reveal details about the radiative and nonradiative relaxations of excitation among these levels. The data indicate a near-resonant cross relaxation among these sites. The D-5(2) and D-5(1) states are observed to decay nonradiatively by filling the D-5(0) state with characteristic times of 2.4 and 2.8 mu s, respectively. The D-5(0) state is found to relax in a manner that depends slightly on the final state and dopant site. (C) 2007 American Institute of Physics.