Photonics @ Interface: Heterogeneous Integrations for Generation, Detection, Conversion, and Modulation

我们将开发一种新型的光子器件，通过结合两个不同的半导体衬底与不同的原子间距。如果晶格间距不同，原子就不能完美地连接在一起，因此很难保证界面的优良质量。我们将通过制造纳米级的微小沟槽来克服这个问题，使原子能够膨胀，从而释放在界面上积累的应变。在原子尺度上，保证界面的质量对于减少缺陷是非常重要的。我们将使用该接口制作一个高灵敏度的探测器，甚至可以识别单个光子（量子光），由于缺陷产生的额外载流子产生的噪声，这是不可能实现的。这种探测器将对未来的量子技术有用，以实现安全通信和强大的交换。我们还将利用该接口开发一种新型的激光和高速光开关。我们的项目总结如下：实现异质集成的新型制造技术：我们将开发新的晶圆级键合工艺技术，以实现无缺陷的优异界面质量。克服键合材料晶格常数和热膨胀常数差异的挑战。我们将为新的粘合技术积累全面的知识。2. Si/Ge雪崩光电二极管和Si/Ge激光器：应变工程界面将使我们能够将Si/Ge雪崩光电二极管（apd）的暗电流降低到可用于在室温下检测单光子的水平。Si/Ge apd也可用于LiDAR（激光成像探测和测距）。接口质量的提高也使Ge在Si衬底上的激光化成为可能，从而实现单片集成。Si/LiNbO3混合光调制器和二次谐波发生器：我们还将在Si衬底上键合LiNbO3，这使我们能够利用LiNbO3的电光和非线性效应，同时保持Si纳米级图像化的优势。带槽波导的混合光调制器将通过去除50欧姆终端以1焦耳功耗运行。混合二次谐波发生器（shg）将转换不同的波长来产生绿光和紫外线光，以便在dvd上写入密度更大的数据。我们认为我们的方法将建立一种新的方法，使异构接口的质量得到提高。晶圆尺度的键合是众所周知的，但在原子尺度上形成完美键合的纳米尺度的键合尚未实现。我们将为纳米电子学和光子学的研究人员积累有关开发界面的各种物理参数（如应变，空隙，粘附和缺陷）的全面知识。

We will develop novel photonic devices by bonding two different semiconductor substrates with different spacing between atoms. It was very difficult to ensure an excellent quality at the interface, because the atoms cannot connect perfectly, if the lattice spacing is different. We will overcome this problem by making nano-scale tiny trenches to allow atoms to expand for releasing the strain accumulated at the interface. The quality of the interface is very important to make sure to reduce defects in the atomic scale. We will use the interface for making a highly sensitive detector to identify even just single photon (quantum of light), which is impossible to realise with defects due to the noise from additional carriers created by defects. This detector will be useful for future quantum technologies to enable secure communications and powerful commutations. We will also develop a novel laser and high speed optical switches by using this interface.Our project is summarised as follows:1. Novel Manufacturing Technologies for Enabling Heterogeneous Integrations: We will develop new wafer-scale bonding process technologies to allow excellent interface qualities without defects. Our challenges to overcome the difference of lattice constants and thermal expansion constants for bonded materials. We will accumulate comprehensive knowledge for new bonding techniques. 2. Si/Ge Avalanche-Photo-Diodes and Si/Ge Lasers: The strain engineered interface will enable us to reduce dark currents of Si/Ge Avalanche-Photo-Diodes (APDs) to the level useful for detecting single photons at room temperature. Si/Ge APDs are also useful for LiDAR (Laser Imaging Detection and Ranging). The improved interface quality also enables to achieve lasing of Ge on a Si substrate towards monolithic integrations.3. Si/LiNbO3 Hybrid Optical Modulator and Second-Harmonic-Generators: We will also bond LiNbO3 on a Si substrate, which allows us to utilise the electro-optic and nonlinear effects of LiNbO3, while keeping the advantages of nanoscale patterning of Si. The hybrid optical modulator with a slot waveguide will be operated at attojoule power consumption by removing the 50 Ohm-termination. The hybrid Second-Harmonic-Generators (SHGs) will convert various wavelengths to generate green and UV lights for much denser data-writing on DVDs.We think our approach will establish a new way of making heterogeneous interface with improved quality. Wafer-scale bonding of a patterned substrate is certainly well-known, but the nano-scale patterning to form perfect bonding in atomic-scale has not yet been achieved, yet. We will accumulate comprehensive knowledge on the developed interface, in terms of various physical parameters such as strains, voids, adhesions, and defects for researchers in nanoelectronics and photonics.