High response solar-blind MgZnO photodetectors grown by molecular beam epitaxy
High response solar-blind MgZnO photodetectors grown by molecular beam epitaxy
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DOI：
10.1117/12.2045555
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发表时间：
2014-03
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影响因子：
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通讯作者：
W. Schoenfeld;M. Wei;R. Boutwell;Huiyong Liu
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文献类型：
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作者：
W. Schoenfeld;M. Wei;R. Boutwell;Huiyong Liu
通过等离子体辅助分子束外延在 c 面蓝宝石衬底上外延生长高质量的 w-MgxZn1-xO 薄膜。通过应用低温成核层，获得了具有高结晶质量、低缺陷和位错密度以及亚纳米表面粗糙度的ZnO薄膜。通过调节Mg/Zn通量比，获得了Mg成分高达x=0.46且无相偏析的纤锌矿MgxZn1-xO薄膜。制造并表征了具有叉指电极几何形状和有效表面积为 1 mm2 的金属-半导体-金属 (MSM) 光电导和肖特基势垒器件。所得器件在 ~260nm 波长处显示出 ~100 A/W 峰值响应度。我们还报道了立方岩盐 c-MgxZn1-xO 薄膜，采用 MgO 基板上的非传统方法，在 MSM 光电探测器中演示日盲光响应，实现混合相和单晶薄膜的峰值响应度分别为 460 A/W (@ 250 nm) 和 12.6 mA/W (@ 240 nm)。这项工作的一个具体重点是确定各种生长参数对 c-MgZnO 探测器性能的影响。
High quality w-MgxZn1-xO thin films were grown epitaxially on c-plane sapphire substrates by plasma-assisted Molecular Beam Epitaxy. ZnO thin films with high crystalline quality, low defect and dislocation densities, and subnanometer surface roughness were achieved by applying a low temperature nucleation layer. By tuning Mg/Zn flux ratio, wurtzite MgxZn1-xO thin films with Mg composition as high as x=0.46 were obtained without phase segregation. Metal- Semiconductor-Metal (MSM) photoconductive and Schottky barrier devices with interdigitated electrode geometry and active surface area of 1 mm2 were fabricated and characterized. Resultant devices showed ~100 A/W peak responsivity at wavelength of ~260nm. We also report on cubic rock salt c-MgxZn1-xO thin films, following a non-traditional approach on MgO substrates, to demonstrate solar-blind photoresponse in MSM photodetectors, realizing a peak responsivity of 460 A/W (@ 250 nm) and 12.6 mA/W (@ 240nm) for mixed phase and single crystal films, respectively. A specific focus of the work is on identifying the impact of various growth parameters on the performance of the c- MgZnO detectors.