A physical model for the reverse leakage current in (In,Ga)N/GaN light-emitting diodes based on nanowires
A physical model for the reverse leakage current in (In,Ga)N/GaN light-emitting diodes based on nanowires
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DOI：
10.1063/1.4940949
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发表时间：
2016-01-28
影响因子：
3.2
通讯作者：
Riechert, H.
中科院分区：
文献类型：
--
作者：
Musolino, M.;van Treeck, D.;Riechert, H.
研究了分子束外延（In，Ga）N/aN纳米线（NW）发光二极管（LED）高反向漏电流的来源。为此，电容深能级瞬态谱（DLTS）和温度依赖的电流-电压（I-V）的测量上进行了充分处理的NW-LED。DLTS测量揭示了在p-i-n结的耗尽区存在两个不同的高浓度电子陷阱。这些带隙态位于导带最小值以下57 +/- 20和84 +/- 30 meV的能量处。讨论了这些深能级态的物理起源。随温度变化的I-V特性，83和403 K之间获得的，表明不同的导电机制导致所观察到的漏电流。在所有这些结果的基础上，我们开发了一个定量的物理模型，在反向偏压制度的电荷输运。通过考虑可变范围跳跃和库仑陷阱态的电子发射的相互作用，后者由声子辅助隧穿和Poole-Frenkel效应描述，我们可以用一组一致的参数在整个温度范围内模拟实验I-V曲线。我们的模型也适用于平面GaN基LED。此外，提出了降低近场发光二极管漏电流的可能途径。(C)2016 AIP Publishing LLC.
We investigated the origin of the high reverse leakage current in light emitting diodes (LEDs) based on (In,Ga)N/aN nanowire (NW) ensembles grown by molecular beam epitaxy on Si substrates. To this end, capacitance deep level transient spectroscopy (DLTS) and temperature-dependent current-voltage (I-V) measurements were performed on a fully processed NW-LED. The DLTS measurements reveal the presence of two distinct electron traps with high concentrations in the depletion region of the p-i-n junction. These band gap states are located at energies of 57 +/- 20 and 84 +/- 30 meV below the conduction band minimum. The physical origin of these deep level states is discussed. The temperature-dependent I-V characteristics, acquired between 83 and 403 K, show that different conduction mechanisms cause the observed leakage current. On the basis of all these results, we developed a quantitative physical model for charge transport in the reverse bias regime. By taking into account the mutual interaction of variable range hopping and electron emission from Coulombic trap states, with the latter being described by phonon-assisted tunnelling and the Poole-Frenkel effect, we can model the experimental I-V curves in the entire range of temperatures with a consistent set of parameters. Our model should be applicable to planar GaN-based LEDs as well. Furthermore, possible approaches to decrease the leakage current in NW-LEDs are proposed. (C) 2016 AIP Publishing LLC.