Gallium nitride (GaN) and aluminium gallium nitride (AlGaN) are promising materials for optoelectronics because of their direct band gap and high electron mobility. However, their optical absorbance being limited to within the ultraviolet (UV) range constrains their deployment in broadband photodetectors. Here, we combine three-dimensional (3D) epitaxial GaN and AlGaN thin films with visible-spectrum active two-dimensional (2D) molybdenum disulphide (MoS₂) to create a 2D/3D hybrid that is active across a broadband spectrum. The interfacial properties of 2D/3D heterojunctions are thoroughly investigated on an industrially compatible silicon platform where a staggered gap (type II) band structure leads to a rectifying heterojunction phenomenon. It is shown that the optical absorbance spectra can be broadened by several hundreds of nanometers using this hybrid approach. As a result, these heterostructures are promising to cover broadband photodetection from ultraviolet (UV)-A (UV-B) to visible solar spectrum, thereby enhancing the practical utility of GaN and its alloys.

中文翻译：

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MoS ₂ / GaN和MoS ₂ / AlGaN异质界面在宽带光检测应用中的电流传输和能带对准研究

氮化镓（GaN）和氮化铝镓（AlGaN）由于具有直接的带隙和高的电子迁移率，因此是有前途的光电子材料。但是，它们的光吸收率被限制在紫外线（UV）范围内，这限制了它们在宽带光电探测器中的部署。在这里，我们将三维（3D）外延GaN和AlGaN薄膜与可见光谱有源二维（2D）二硫化钼（MoS ₂）以创建在宽带频谱中有效的2D / 3D混合动力。在工业兼容的硅平台上彻底研究了2D / 3D异质结的界面特性，其中交错的间隙（II型）能带结构导致整流异质结现象。结果表明，使用这种混合方法可以将光吸收光谱扩大数百纳米。结果，这些异质结构有望覆盖从紫外（UV）-A（UV-B）到可见太阳光谱的宽带光检测，从而提高GaN及其合金的实用性。