Interface structure and luminescence properties of epitaxial PbSe films on InAs(111)A
Interface structure and luminescence properties of epitaxial PbSe films on InAs(111)A
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DOI：
10.1116/6.0000774
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发表时间：
2021-03-01
影响因子：
2.9
通讯作者：
Mukherjee, Kunal
中科院分区：
文献类型：
--
作者：
Haidet, Brian B.;Nordin, Leland;Mukherjee, Kunal
窄隙 IV-VI 和 III-V 半导体的外延异质结构为新型电子学和中红外光子学提供了平台。然而，岩盐 IV-VI 和闪锌矿 III-V 之间的键合和晶体结构存在明显差异，要求开发成核和生长方案以可靠地制备高质量异质结构。在这项工作中，我们展示了在几乎晶格匹配的 InAs (111)A 模板上制备单晶 (111) 取向 PbSe 外延薄膜的途径。如果没有这种技术，高能异价界面很容易产生两个 PbSe 晶粒群，它们相对于彼此面内旋转 180 度，并由旋转孪晶边界分隔开。我们发现，用 PbSe 助熔剂进行高温表面处理会消除其中一种界面堆积，从而产生具有由单层扭曲 PbSe 介导的界面的单晶薄膜。虽然非常薄的 PbSe-on-InAs 薄膜不发光，暗示着 III 型能带排列，但我们看到 1.5 μm 厚的薄膜在低激发条件下具有强烈的室温光致发光，少子寿命为 20 ns，在高激发条件下双分子复合，即使螺纹位错密度超过 10(8)cm(-2)。我们还注意到，尽管这些薄膜的热膨胀与基板不匹配，但它们几乎完全应变松弛，即使在低温下，位错也会滑动以减轻应变。这些结果揭示了 IV-VI 半导体的卓越特性以及适用于光电子领域一系列应用的新型 IV-VI/III-V 接口。
Epitaxial heterostructures of narrow-gap IV-VI and III-V semiconductors offer a platform for new electronics and mid-infrared photonics. Stark dissimilarities in the bonding and the crystal structure between the rocksalt IV-VIs and the zincblende III-Vs, however, mandate the development of nucleation and growth protocols to reliably prepare high-quality heterostructures. In this work, we demonstrate a route to single crystal (111)-oriented PbSe epitaxial films on nearly lattice-matched InAs (111)A templates. Without this technique, the high-energy heterovalent interface readily produces two populations of PbSe grains that are rotated 180 degrees in-plane with respect to each other, separated by rotational twin boundaries. We find that a high-temperature surface treatment with the PbSe flux extinguishes one of these interfacial stackings, resulting in single-crystalline films with interfaces that are mediated by a monolayer of distorted PbSe. While very thin PbSe-on-InAs films do not emit light, hinting toward a type-III band alignment, we see strong room temperature photoluminescence from a 1.5 mu m thick film with a minority carrier lifetime of 20ns at low-excitation conditions and bimolecular recombination at high excitation conditions, respectively, even with threading dislocation densities exceeding 10(8)cm(-2). We also note near-complete strain relaxation in these films despite large thermal expansion mismatch to the substrate, with dislocations gliding to relieve strain even at cryogenic temperatures. These results bring to light the exceptional properties of IV-VI semiconductors and the new IV-VI/III-V interfaces for a range of applications in optoelectronics.