Ultrasensitive vapor phase ion detection by one dimensional and two-dimensional nanomaterials

Abstract

Ion detectors, or radiation sensors, are drawing tremendous interests because of their widespread applications in environmental control and monitoring, medical diagnosis, public security, space exploration, and a variety of industries. High sensitivity, miniature size, low power consumption ion detectors with the ability to monitor ions in the real-time are always pursued by researchers and will significantly impact our normal life. For the future ion detectors, there are several important criteria: (1) small size and light weight; (2) operate at millitorr pressure or higher; (3) produce high gain and maintain low noise while operating at elevated pressures; (4) exhibit long detector lifetime; (5) withstand periodic venting to the atmosphere; (6) tolerate storage at atmospheric pressure. For current commercial ion detectors, such as Faraday cup and electron multipliers, they are impossible to fulfill these requirements. Faraday cup has the simple structure but with poor sensitivity, in contrast, electron multipliers have enough high sensitivity but with very complex structure, very high working voltage and low working pressure. Carbon nanotube and graphene, which are as the typical one dimensional and twodimensional materials, attract significant attention due to their very sensitive electrical response to various analysts mainly owing to their unique structures and excellent transport properties. They have been developed and incorporated into many fields, such as I sincerely appreciated all the people who ever helped and supported me to complete this work. In particular, I would love to express my hearty appreciation to my research advisor, Prof. Yung Joon Jung, for his sustained guidance and direction, numerous support and encouragement during my research time, and also sincerely advice and kind help for my life. And I also would like to express my deep appreciation to my co-advisor, Prof. Swastik Kar, for his continued guidance, direction, and support in my research, and also useful personal advice for my life. I will always remember the time working with them.

Unraveling the Extraordinary Anisotropic Magnetoresistance in Antiferromagnetic Perovskite Heterostructures: A Case Study of CaMnO3/CaIrO3 Superlattice

“…The insertion of additional insulating SrTiO 3 -blocking layers hinders the electronic hopping and exchange coupling along the c-axis, causing a decrease in interlayer coupling. Both Sr 2 IrO 4 and 1/1-SL exhibit net magnetizations originating from the canting of the AFM moments within the IrO 2 plane [22]. The coupling of LaNiO 3 to the insulating FM LaMnO3 at the interface can lead to the stabilization of an induced AFM order in the [111] direction, which can generate interlayer AFM coupling between two LaMnO 3 layers separated by 7 u.c of LaNiO 3 , as suggested by the authors in a separate study [21].…”

“…In contrast, the absence of the kink pattern in (MIx2) 5 (x = 4, 5, 8) represents the absence of fieldpseudospin coupling. Thus, the AMR mechanism in (MIx2) 5 (x = 4, 5, 8) SLs is mainly governed by orthorhombic distortion through S-L coupling restoring the sinusoidal resistance [22].…”

“…In epitaxial thin films, the dimensionality of the system can be tuned by controlling the thickness of the film. It has been found that reducing the dimensionality in epitaxial thin films can increase U and induce pseudospin-based emergent magnetism in SrIrO 3 and CaIrO 3 [21][22][23][24]. This emergent magnetism arises from the system's delicate balance between SOC and U.…”