Analysis of nouradiative carrier recombination processes in InN films by mid-infrared spectroscopy
Analysis of nouradiative carrier recombination processes in InN films by mid-infrared spectroscopy
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中红外光谱分析 InN 薄膜中的无辐射载流子复合过程
DOI：
10.1007/s11664-013-2550-y
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发表时间：
2013
影响因子：
2.1
通讯作者：
and Akihiko Yoshikawa
中科院分区：
文献类型：
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作者：
Daichi Imai;Yoshihiro Ishitani;Masayuki Fujiwra;X. Q. Wang;Kazuhide Kusakabe;and Akihiko Yoshikawa
我们研究了两种载流子复合过程对InN带边辐射复合效率的影响：深态辐射复合和非辐射复合(NR)。由于禁带宽度较小和表面电子积累层的存在，很难观察到载流子通过深态的跃迁过程。我们通过使用中红外光致发光(PL)测量来解决这个问题，并在室温下观察到约0.32 eV的发射峰，我们认为这是通过深缺陷态的跃迁过程引起的。由于这种发射弱于带边发射，因此我们认为主要的载流子复合过程是声子发射引起的。已知的NR率由NR缺陷密度、载流子到NR缺陷的传输过程以及载流子的热激活过程决定。利用不同载流子迁移率的p型样品研究了NR缺陷的载流子输运和俘获过程。结果表明，负载率受载流子输运的影响很大，负载型缺陷主要是点缺陷和受体性质的络合物。我们还观察到了热导率与带边发光强度之间的关系。结果发现，InN中的载流子输运和热激活过程对Nr速率有很大的影响。
We investigate the reduction in the efficiency of band-edge radiative recombination in InN by two carrier recombination processes via mid-gap states: radiative recombination via deep states and nonradiative recombination (NR). Because of the small band-gap energy value and the existence of the surface electron accumulation layer, the carrier transition processes via deep states cannot be observed easily. We address this problem by using mid-infrared photoluminescence (PL) measurements, and observe an emission peak around 0.32 eV at room temperature, which we interpret as being caused by transition processes via deep-defect states. Since this emission is weaker than the band-edge emission, the dominant carrier recombination process is concluded to be NR by phonon emission. The NR rate is known to be determined by the NR defect density, carrier transport processes to NR defects, and thermal activation processes of carriers. Carrier transport and capture processes by NR defects are investigated usingp-type samples for various carrier mobility values. It is concluded that the NR rate is highly affected by the carrier transport, and that the candidates for the NR defect species are point defects and complexes of acceptor nature. We have also observed the correlation between the thermal conductivity and the band-edge PL intensity. As a result, we have found that the NR rate is highly affected by the carrier transport and thermal activation processes in InN.