Nonradiative centers in deep-UV AlGaN-based quantum wells revealed by two-wavelength excited photoluminescence
Nonradiative centers in deep-UV AlGaN-based quantum wells revealed by two-wavelength excited photoluminescence
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双波长激发光致发光揭示深紫外 AlGaN 量子阱中的非辐射中心
DOI：
10.1002/pssb.201451582
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
and H. Hirayama
中科院分区：
文献类型：
--
作者：
N. Kamata;A. Z. M. Touhidul Islam;M. Julkarnain;N. Murakoshi;T. Fukuda;and H. Hirayama
我们通过双波长激发光致发光 (PL) 方案成功检测了 InAlGaN 多量子阱 (MQW) 中 265 nm 左右消毒波长的非辐射复合 (NRR) 中心。研究的样品是采用金属有机化学气相沉积 (MOCVD) 技术在蓝宝石 (0001) 衬底上生长的 InAlGaN 多量子阱结构，其具有 InAlGaN 电子阻挡层，生长温度为 880°C（样品 A）和 920°C（样品 B）。 MQW 由三个 2nm 的 InAlGaN 阱组成，中间夹有 7nm 的 InAlGaN 势垒层。添加 1.17eV 的带隙下激发 (BGE) 光后，样品 A 的 PL 强度降低，但样品 B 的 PL 强度增加。PL 强度的两种变化都表明存在被 BGE 激活的 NRR 中心。我们将强度变化分别归因于双水平模型和单水平模型。基于速率方程分析，利用PL强度变化的饱和趋势确定了样品B的一组NRR参数。该方法的光谱和定量优势使我们能够在不提供电极的情况下阐明NRR中心的能量分布。
We have succeeded in detecting nonradiative recombination (NRR) centers in InAlGaN multiple quantum wells (MQWs) for the sterilization wavelength at around 265 nm by our scheme of two‐wavelength excited photoluminescence (PL). Samples studied are InAlGaN multiple quantum well structures with InAlGaN electron blocking layer grown on sapphire (0001) substrates by metal‐organic chemical vapor deposition (MOCVD) technique at the growth temperature of 880 °C (sample A) and 920 °C (sample B). The MQW consists of three InAlGaN wells of 2 nm sandwiched by 7 nm InAlGaN barrier layers. With the addition of the below‐gap excitation (BGE) light of 1.17 eV, the PL intensity decreased for the sample A but increased for the sample B. Both change in the PL intensity implies the existence of NRR centers, which were activated by the BGE. We attribute both intensity change to two‐levels model and one level model, respectively. Based on rate equation analysis, a set of NRR parameters of sample B was determined by utilizing a saturating tendency of the PL intensity change. Spectroscopic and quantitative advantages of the method enable us to clarify energy distribution of NRR centers without providing electrode.