Hot-embossing Preparation Of Ge-Sb-Se Chalcogenide Optical Waveguide

Chalcogenide glasses have attracted great attention in all-optical signal processing and infrared biosensing,owing to its excellent properties like high non-linear refractive index,ultrafast non-linear response time,broad infrared transparency,as well as its unique photosensitivity.With the vigorous development of integrated photonic theory and technology,the combination of chalcogenide materials and integrated photonics has formed a unique research field —“chalcogenide photonics”.Chalcogenide photonics has become one of the hottest research field of photonics.Some international well-known research institutions have achieved a series of innovative research results in the preparation and application of chalcogenide optical waveguide.And among them,the thermal nano-imprint technology has become a research hotspot in the field of preparation of chalcogenide optical waveguide at home and abroad because of its advantages such as simple operation,high resolution,short cycle and low cost.In this paper,high-quality Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ chalcogenide films are prepared by magnetron sputtering using homemade Ge-Sb-Se glass targets by our laboratory,and then their various properties were systematically analyzed.In addition,we fabricated Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ waveguides by hot-embossing and studied the influence of different process parameters on the quality of the embossing waveguide.Details are as follows:?1?Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ chalcogenide glass having a diameter of 50 mm were prepared by melt quenching method in vacuum environment and then cut and processed into samples with 3mm thick for magnetron sputtering to prepare Ge-Sb-Se amorphous films.?2?The amorphous Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ thin films were prepared by magnetron sputtering deposition technique,respectively.The transformation of optical properties of thin films after heat treatment has been investigated.Results indicate that when the annealing temperature?Ta?is lower than the glass transition temperature?Tg?,crystallization does not happen.And with the increase of Ta,the optical band gap increases and the refractive index decreases.But when the annealing temperature?Ta?is higher than the glass transition temperature?Tg?,the film begins to crystallize and precipitate grains.And with a further increase of Ta,the volume of grains and the refractive index increases and the optical band gap decreases.Using the Mott-Davis energy band structure model,we analyze that the increase or decrease of the defects and the hanging bonds in the films is an important factor leading to the change of optical band gap and refractive index.?3?Amorphous Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ thin films were prepared by radio-frequency magnetron sputtering and the hot embossing experiments were carried out by using the existing hot embossing platform to study the effect of different process parameters on the quality of embossed waveguide.After a large number of experiments,we finally prepared the corresponding high-quality chalcogenide optical waveguides,and achieved the best thermal embossing process parameters of Ge₁₅Sb₂₀Se₆₅ and Ge_12.5Sb₁₀Se_77.5 films,respectively: imprinting temperature is 254? and 168?,time is 25 min and 20 min,imprinting gas pressure is 0.5Mpa and 0.4Mpa,cooling rate is 20? / min and 15? / min,demolding temperature is 185? and 100?.The experimental results show that the Ge_12.5Sb₁₀Se_77.5 and Ge₁₅Sb₂₀Se₆₅ films successfully reproduce the microstructure of the mold under the optimum conditions,and no cracks or crystallization phenomena occur.