Large‐Area Tellurium/Germanium Heterojunction Grown by Molecular Beam Epitaxy for High‐Performance Self‐Powered Photodetector
Large‐Area Tellurium/Germanium Heterojunction Grown by Molecular Beam Epitaxy for High‐Performance Self‐Powered Photodetector
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DOI：
10.1002/adom.202101052
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发表时间：
2021-08
影响因子：
9
通讯作者：
Beining Zheng;Zehan Wu;Feng Guo;Ran Ding;Jianfeng Mao;M. Xie;S. Lau;J. Hao
中科院分区：
文献类型：
--
作者：
Beining Zheng;Zehan Wu;Feng Guo;Ran Ding;Jianfeng Mao;M. Xie;S. Lau;J. Hao
作为一种有吸引力的元素半导体材料，具有窄带隙的p型碲（Te）提供高载流子迁移率，在宽光谱范围内的强光-物质相互作用以及良好的化学稳定性，这激发了光电器件的潜力。然而，弱的载流子分离和放大潜力的模糊限制了其应用。在这项工作中，Te和传统的半导体锗（Ge）的集成设计。通过分子束外延（MBE）方法，在Ge衬底上直接沉积具有高结晶度的大面积且均匀的Te膜。Te和Ge层之间功函数的差异导致内建电场，其可以有效地增强载流子分离。结果表明，在近红外光（980 nm，2.15 µW cm−2）照射下，MBE生长的Te/Ge垂直异质结具有良好的自供电光伏性能，电流开/关比超过103，响应率（R）为523 mA W−1，比探测率（D*）为9.50 × 1010 cm Hz 1/2 W−1。此外，该异质结构的优异稳定性和高响应速度为多用途光电器件提供了重要的应用价值。
As an attractive elemental semiconductor material, p‐type tellurium (Te) with a narrow bandgap provides high carrier mobility, strong light–matter interactions in a wide spectral range, and good chemical stability, which enlightens the potential in optoelectronic devices. However, the applications are impeded by weak carrier separation and vague potential in scaling‐up. In this work, the integration of Te and conventional semiconductor germanium (Ge) is designed. Through molecular beam epitaxy (MBE) method, large‐area and uniform Te films with high crystallinity are directly deposited on the Ge substrates. The difference in work function between Te and Ge layer leads to a built‐in electric field, which can effectively enhance the carrier separation. As a result, a self‐powered splendid photovoltaic performance is observed in the MBE grown Te/Ge vertical heterojunction with current on/off ratio over 103, responsivity (R) 523 mA W−1, and specific detectivity (D*) 9.50 × 1010 cm Hz1/2 W−1 when illuminated by near‐infrared light (980 nm, 2.15 µW cm−2). Furthermore, excellent stability and high response speed of the ultrathin heterostructure offer a significant application value for multipurpose photoelectric devices.