New and Emerging Low Dimensional Photonic Devices and Applications
Light manipulation and control at the nanoscale is becoming an important feature, mainly due to applications in wireless communications, fiber optics, energy devices, etc. Photon generation at the nanoscale can be highly efficient owning to their low power consumption. Here, we fabricate and test photonic devices and characterize their performance compared to commercially available devices.
Tunable Light Emission at The Nanoscale
Tunable light emission at the nanoscale can be accomplished by doping the material. Various groups have demonstrated this tunable light emission using this technique. Nevertheless, owning to their tunable band gap with the number of layers, layered 2D materials can exhibit tunable photoluminescence. However, the spectral resolution of such technique is limited since this process depends on the intrinsic properties of each number of 2D layer. Using thermal processes, we demonstrate tunable photoluminescence with high spectral resolution. This tunable light emission is caused by the formation of stable black phosphorus oxide, which is an under investigated material. Using our Raman and photoluminescence measurements, the tunability resolution can be as small as 5nm with tunablity bandwidth of between 590-730nm.
Further characterization of this tunable photoluminescence reveals that different compositions of black phosphorus oxide grow on the surface of layered black phosphorus. In fact, this tunable light emission emerges from the tunable band gap of black phosphorus oxide, where this band gap is highly dependent on the oxygen concentration. This tunable light emission can be promising for LED and photonic device applications.
Low-Cost Solution Processed Van der Waals Photovoltaics
Photovoltaic devices based on low dimensional materials are predicted to exhibit a high solar cell efficiency. Due to the high electron mobility and layer tunable band gap, 2D materials can be a promising route for high efficiency solar cells. However, fabrication challenges and environmental effects can significantly degrade the the solar cell behavior. In this work, we fabricate low cost photovoltaics using solution processed nanomaterials. The fabricated solution is then deposited on the desired structure. An advantage these solar cells exhibit is how the solution is integrated with the solar cell structure, where simple Van der Waals deposition techniques are tested. We characterize these different photovoltaics for the best efficiencies possible, which is a step towards low cost energy generation.