Synthesis and structural characterization of vertical ferromagnetic MnAs/semiconducting InAs heterojunction nanowires

Abstract

The purpose of this study is to synthesize vertical ferromagnetic/semiconducting heterojunction nanowires by combing the catalyst-free selective-area growth of InAs nanowires and the endotaxial nanoclustering of MnAs and to structurally and magnetically characterize them. MnAs penetrates the InAs nanowires to form nanoclusters. The surface migration length of manganese adatoms on the nanowires, which is estimated to be 600 nm at 580 °C, is a key to the successful fabrication of vertical MnAs/InAs heterojunction nanowires with atomically abrupt heterointerfaces.

Shape control of ferromagnetic MnAs nanoclusters exhibiting magnetization switching in vertical MnAs/InAs heterojunction nanowires

“…The fabrication process for heterojunction NWs was mostly similar to that reported elsewhere. 26) First, we prepared the initial circular openings, which were arranged and defined in SiO 2 thin films by electron beam lithography. There were various types of initial circular openings, i.e., different diameters (d o ) and distances between them, or periods (a) formed at the same time on the same GaAs (111)B substrates.…”

“…We have observed similar heterojunctions by TEM for a comparable sample characterized in our previous study. 26) shows an ED pattern obtained from the area around a heterointerface between MnAs NC and InAs NW, in which MnAs NC was formed on a top {111}B crystal facet of the host InAs NW. From these structural characterization results, we concluded that hexagonal NiAs-type MnAs NCs, which were mainly composed of manganese and arsenic elements, were grown on the host zinc-blende-type InAs NWs.…”

“…In addition, we have successfully demonstrated the fabrication of vertical MnAs=InAs heterojunction NWs using InAs as a semiconducting NW template material, and we have reported on magnetic characterization results and possible growth mechanisms on the basis of the results of our detailed structural characterization. 26) Some of the main reasons why we have chosen the vertical MnAs=InAs heterojunction NWs are as follows. (i) In the case of the vertical free-standing NWs, we can expect nanometer-scale heterojunctions with misfit-dislocation-free heterointerfaces or with a markedly decreased number of misfit dislocations compared with flat layers, even in the case of a material system with a lattice mismatch larger than 10%.…”

Anomalous Angle-Dependent Magnetotransport Properties of Single InAs Nanowires

“…The growth direction of the nanowires is parallel to the ⟨111⟩ B direction of the substrate. A detailed description of the growth process can be found in ref . After growth, the nanowires were detached from the substrate by ultrasonic vibration in isopropanol solution and dripped on an oxidized Si(111) substrate.…”

Low-temperature grown MnAs/InAs/MnAs double heterostructure on GaAs (111)B by molecular beam epitaxy

“…The promotion of smooth surface growth and preservation of an adequate rate of growth can both be accomplished by changing the V/III ratio within the ideal range. There is a few reports of MnAs growth on InAs, 24) LT growth of InAs on glass/plastic substrate 25) and MnAs/InAs/MnAs thin trilayer on GaAs(111)B, 26) but to the best of our knowledge, no papers have been published that specifically investigate MnAs/InAs/MnAs thick double heterostructure on GaAs(111)B for the purpose of vertical spin-FET application. This underscores the novelty and significance of the present study, as it seeks to contribute valuable insights and fill this critical void in scientific literature.…”