Photonics is one of the largest and fasted growing markets of the world economy. Optical technologies are key to a vast range of applications from telecommunications networks to sensor and metrology equipment and are being actively developed by industrial giants such as IBM, Intel and Cisco. In a similar way to the evolution experienced by electronics, the demand for photonics devices with smaller footprint, lower cost and higher functionality has propelled the rapid development of integrated "photonics chips". Thanks to the legacy provided by decades of enormous investments in the electronic industry, silicon is rapidly becoming the standard material platform for photonic integrated chips. However, because of its crystalline structure, silicon is a very poor light emitter and, therefore, truly integrated devices that can emit, process and detect light on-chip still represent a major challenge. III-V semiconductor materials such as InP or GaAs provide far better performance in terms of light emission but cannot compete with silicon in terms of large volume manufacturing and cost. Combining the "best from the two worlds", i.e. heterogeneously integrating III-V light emitters on a silicon material platform, is regarded as a promising solution to circumvent the deficiencies of silicon yet keeping compatibility with industrial silicon manufacturing paradigms to allow scaling to wafer level complex products without requiring a full retooling of the supply chain. Building on established expertise in photonic integrated devices and transfer printing technologies at Glasgow and Strathclyde universities, this proposal will develop an assembly technique to integrate active III-V membrane devices onto passive silicon photonic integrated circuits. The method will demonstrate parallel transfer of multiple devices with sub-micrometer positional accuracy and scalability to wafer-level production. The developed techniques will exploit fully back-end processes, making them compatible with current foundry standards and therefore commercial interests. Key demonstrators in optical communications, gas sensing and high density data storage will be developed to illustrate the flexibility of the methods and potential across a wide range of application spaces. The project will benefit from the support from several academic and industrial partners who will provide resources and expertise in key areas such as wafer-scale manufacturing of III-V optical devices (CST), transfer printing system engineering (Fraunhofer), optical transceivers for telecomm and datacentre markets (Huawei), micro-assembly of active/passive photonic systems (Kaiam), integrated photonic devices for HDD data storage (Seagate), mid-IR gas sensors (GSS), large-scale silicon photonics devices (Southampton University). The proposal aligns with EPSRC's Manufacturing the Future theme and the Photonics for Future Systems priority, and addresses specific portfolio areas such as Manufacturing Technologies, Optical Communications, Optical Devices & Subsystems, Optoelectronic Devices & Circuits, Components & Systems

The rapidly developing technique of transfer printing on the micro and nanoscales allows the manufacture of high quality, high performance devices on a wide range of substrates in almost any location. This highly versatile capability features a high-precision mechanical pick-and-place assembly technique that utilises the adhesive properties of soft stamps, and the technology has only recently broken into the field of electronics and photonics. Placing this exciting and highly important development into context, in the 1990s Whitesides (Harvard University Chemistry Dept.), a pioneer in microfabrication and nanotechnology, established the ground-breaking concept of patterning self-assembled monolayers for lithographic, sensing, medical and pharmaceutical applications and termed this micro-contact printing. From this foundation, the technique has evolved into much higher levels of complexity in which micro-transfer printing has recently delivered micro- LED arrays that, for example, feature in flexible displays and provide inorganic analogues of flexible organic light-emitting diodes (OLEDs) - something that was previously thought to be extremely challenging if not impossible. In this programme, 'Hetero-print', we aim to rapidly push this exciting field further by establishing, for the first time and ahead of the international competition, new routes towards the manufacture of heterogeneous devices, consisting of integrated systems made from pure and/or hybrid inorganic/organic materials. The demand for these hybrid approaches is extremely high, because it opens up the prospect of multifunctional devices that organic materials can deliver in tandem with inorganic semiconductor technology. The ambition of Hetero-print is to deliver micro- and nano-transfer printing as the technology for the versatile and scalable manufacture of heterogeneous materials, structures and devices. In achieving this, we will introduce significant new capabilities for the manufacture of electronic, photonic, and other systems, which complement and are synergistic with those of established semiconductor mass-manufacturing methods including vacuum deposition and solution processing. In this respect, transfer printing is a highly scalable technique and perfectly suited to high volume manufacture, allowing >10,000 micro-sized integrated circuits to be processed in a single run. An issue with many photonic devices is cost, but micro-transfer printing can be economical with the number of print cycles from a single stamp running into the tens of thousands; the technique is also economical in terms of materials waste, providing a methodology to manufacture multiple-array devices in very high yield.