Fully photon operated transmistor / all-optical switch based on a layered Ge1Sb2Te4 phase change medium

We propose an alternative device concept which represents the foundation for future fully photon operated logic circuits based on an optically active medium. The device has the potential to decrease energy consumption and simultaneously to significantly increase computational operation speed. We call this all-optical switch device a “transmistor”, since in this alternative concept a controllable train of photon pulses (optical gate) initializes substantial changes of the optical transmittance of an optically active medium by inducing structural changes therein. First results of a fully photon operated prototype of a transmistor device based on a layered phase change Ge1Sb2Te4 nano-membrane are presented. The transmittance changes of the nano-membrane‘s material structure determine the transmitted optical power in the functionally arranged optical device

Cutting-edge nano-LED technology

In this Perspective, we will introduce possible future developments on group III-nitride nano-LEDs, which are based on current achievements in this rapidly arising research-technological field. First, the challenges facing their fabrication and their characteristics will be reported. These developments will be set in a broader context with primary applications in lighting, display technology, biology, and sensing. In the following, we will center on advanced applications in microscopy, lithography, communication, and optical computing. We will discuss unconventional device applications and prospects for emerging photon source-based technologies. Beyond conventional and current achievements in optoelectronics, we will present hybrid nano-LED architectures. Novel device concepts potentially could play an essential role in future photon source developments and serve as a key component for optical computing. Therefore, forefront fully photon operated logic circuits, photon-based computational processors, and photon driving memories will be discussed. All these developments will play a significant role in a future highly secure, low energy consuming green IT. Besides today’s environmentally friendly terrestrial industrial and information technologies, an enormous potential of nano-LED technology for a large range of applications especially in the next stage of space research is envisaged

Nano-LED induced chemical reactions for structuring processes

We present a structuring technique based on the initialization of chemical reactions by an array of nano-LEDs which is used in the near-field as well as in the far-field regime. In the near-field regime, we demonstrate first results with the nano-LED array for lithography using the photoresist DiazoNaphthoQuinone-(DNQ)-sulfonate for the fabrication of holes in the resist down to ∼75 nanometres in diameter. In contrast, the nano-LEDs can also be employed in the far-field regime to expose thin films of the monomer bisphenol A-glycidyl methacrylate (Bis-GMA) and to initialize polymerization locally. Photosensitive films were patterned and spherical cone-shaped three dimensional objects with diameters ranging from ∼480 nm up to 20 micrometres were obtained. The modification in the material as a result of the photochemical reaction induced i.e. by polymerization was confirmed by Raman spectroscopy. This structuring maskless technique has the potential to induce substantial changes in photosensitive molecules and to produce the desired structures from the tens of microns down to the nanometre scale

Nano-LED driven phase change evolution of layered chalcogenides for Raman spectroscopy investigations

We present a device driving testing platform based on vertically integrated nano light emitting diodes (nano- LEDs). The nano-LEDs with a peak wavelength emission centered at ~ 445 nm were arranged in arrays and conditioned using a laser-micro-annealing process to individually tune their intensity. They were coupled with freestanding monocrystalline Ge1Sb2Te4 nano-membranes with three different thicknesses (~40, ~ 60 and ~ 90 nm) with the aim of initializing ultrafast switching processes and of observing phase changed states simulta- neously by Raman spectroscopy. Raman spectroscopy studies reveal that the optical pulses emitted from the nano-LEDs induce substantial, local changes in the nano-membranes’ states of the Ge1Sb2Te4 layered material. Beside the crystalline state in non-exposed areas (as-grown material), amorphous and different intermediate states were identified in exposed areas as island-like structures with diameters ranging from ~ 300 nm up to ~ 1.5 µm. The latter confirms the nano-LEDs’ emission role in both near- and far-field regimes, depending on the distance between nano-LED and nano-membrane, for driving i.e. inducing the phase change process. The results presented demonstrate the suitability and potential of the vertically integrated nano-LEDs as the key components for a testing platform/for electro-optical convertors driving phase change processes in optically active media. They could also play an important role in the development of future, e.g., non-volatile data storage as well as in optical and neuromorphic computing architectures based on transmistor devices