基于氮化硼薄牺牲层的传递技术可以允许在蓝宝石基材上生长高性能氮化镓气体传感器，然后转移到金属或柔性聚合物载体材料上。该技术可促进生产低成本的可穿戴，移动和一次性传感装置，用于各种环境应用。
将氮化镓的感觉rs to metallic foils and flexible polymers doubles their sensitivity to nitrogen dioxide gas, and boosts response time by a factor of six. The simple production steps, based on metal organic vapor phase epitaxy (MOVPE), could also lower the cost of producing the sensors and other optoelectronic devices.
用新工艺生产的传感器可以在零件的份量中检测氨，并区分含氮气体。气体传感器制造技术在11月9日在期刊中报告Scientific Reports.
“机械地，我们只是将这些器件从基板上剥离，如洋葱的剥离层，”格鲁吉亚科技洛林省梅茨，法国电气与计算机工程学院教授（ECE）的教授Abdallah Ougazzanden。“我们可以将这一层放在另一个可能是灵活的，金属或塑料的支持下。这种技术真的为新功能，新设备和商业化开辟了大量的机会。“
研究人员通过在大约1,300摄氏度的MOVPE过程中在两英寸蓝宝石晶片上生长氮化硼的单层来开始该过程。氮化硼表面涂层仅厚，厚度几纳米，并产生具有强平面表面连接的晶体结构，但垂直连接弱。
Aluminum gallium nitride (AlGaN/GaN) devices are then grown atop the monolayers at a temperature of about 1,100 degrees Celsius, also using an MOVPE process. Because of the boron nitride crystalline properties, the devices are attached to the substrate only by weak Van der Waals forces, which can be overcome mechanically. The devices can be transferred to other substrates without inducing cracks or other defects. The sapphire wafers can be reused for additional device growth.
“This approach for engineering GaN-based sensors is a key step in the pathway towards economically viable, flexible sensors with improved performances that could be integrated into wearable applications,” the authors wrote in their paper.
So far, the researchers have transferred the sensors to copper foil, aluminum foil and polymeric materials. In operation, the devices can differentiate between nitrogen oxide, nitrogen dioxide, and ammonia. Because the devices are approximately 100 by 100 microns, sensors for multiple gases can be produced on a single integrated device.
“Not only can we differentiate between these gases, but because the sensor is very small, we can detect them all at the same time with an array of sensors,” said Ougazzaden, who expects that the devices could be modified to also detect ozone, carbon dioxide and other gases.
氮化镓传感器可以从工业到车辆发动机的各种应用 - 以及可穿戴式传感装置。由于其具有高热和化学稳定性，因此该装置具有吸引力。
“The devices are small and flexible, which will allow us to put them onto many different types of support,” said Ougazzaden, who also directs the International Joint Research Lab at Georgia Tech CNRS.
为了评估将设备转移到不同基板的效果，研究人员在原始蓝宝石晶片上测量了装置性能，并将其与新金属和聚合物基材的性能进行比较。它们感到惊讶地看到传感器灵敏度的加倍和响应时间的六倍增加，可以通过设备中简单的热变化来预期的变化。
“Not only can we have flexibility in the substrate, but we can also improve the performance of the devices just by moving them to a different support with appropriate properties,” he said. “Properties of the substrate alone makes the different in the performance.”
In future work, the researchers hope to boost the quality of the devices and demonstrate other sensing applications. “One of the challenges ahead is to improve the quality of the materials so we can extend this to other applications that are very sensitive to the substrates, such as high-performance electronics.”
The Georgia Tech researchers have previously used a similar technique to produce light-emitting diodes and ultraviolet detectors that were transferred to different substrates, and they believe the process could also be used to produce high-power electronics. For those applications, transferring the devices from sapphire to substrates with better thermal conductivity could provide a significant advantage in device operation.
Ougazzaden and his research team have been working on boron-based semiconductors since 2005. Their work has attracted visits from several industrial companies interested in exploring the technology, he said.
“我非常兴奋,幸运这样热的topic and top-notch technology at GT-Lorraine,” said Taha Ayari, a Ph.D. student in the Georgia Tech School of ECE and the paper’s first author.
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