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

我们将借由键合两个不同原子间距的半导体基板来发展新颖的光子元件。这是非常困难的，以确保良好的质量在界面上，因为原子不能完美地连接，如果晶格间距是不同的。我们将通过制造纳米尺度的微小沟槽来克服这个问题，以允许原子膨胀以释放在界面处积累的应变。界面的质量对于确保在原子尺度上减少缺陷非常重要。我们将使用该界面来制造高灵敏度的探测器，以识别甚至只是单个光子（光量子），这是不可能实现的缺陷，由于来自缺陷产生的额外载流子的噪声。这种探测器将有助于未来的量子技术实现安全通信和强大的通信。我们还将利用该接口研制新型激光器和高速光开关。实现异构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，以实现无缺陷的出色界面质量。我们的挑战是克服键合材料的晶格常数和热膨胀常数的差异。我们将为新的键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（激光成像检测和测距）。改善的界面质量也使得能够实现Ge在Si衬底上的激光发射朝向单片集成。Si/LiNbO 3混合光调制器和二次谐波发生器：我们还将LiNbO 3键合在Si衬底上，这使我们能够利用LiNbO 3的电光和非线性效应，同时保持Si纳米级图案化的优势。通过去除50欧姆终端，具有缝隙波导的混合光调制器将以阿焦耳功耗工作。混合二次谐波发生器（SHG）将转换不同的波长产生绿色和紫外光，以实现更密集的DVD数据写入，我们认为我们的方法将建立一种新的方式来制作具有更高质量的异构接口。图案化衬底的晶片级键合当然是众所周知的，但是形成原子级完美键合的纳米级图案化尚未实现。我们将为纳米电子学和光子学的研究人员积累有关已开发界面的全面知识，包括各种物理参数，如应变，空隙，粘附和缺陷。

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.