Heterogeneous deformation of two-dimensional materials for emerging functionalities

Jin Myung Kim, Chullhee Cho, Ezekiel Y. Hsieh, SungWoo Nam

The authors review mechanical characteristics, uncontrolled inherent deformation and extrinsic heterogeneity, and experimental strategies for controlled heterogeneous deformation of 2D materials, in addition to 3D structure-induced novel functionalities via crumple/wrinkle, or Kirigami, structures, and heterogeneous strain-induced functionalities in exciton and phase engineering. They also present programmable and controlled spatial tunability of 2D material interactions with photons, electrons, and molecules for electronic, optical, and optoelectronic applications. doi.org/10.1557/jmr.2020.34

Manufacturing strategies for wafer-scale two-dimensional transition metal dichalcogenide heterolayers

Mengjing Wang, Hao Li, Tae-Jun Ko, Mashiyat Sumaiya Shawkat, Emmanuel Okogbue, Changhyeon Yoo, Sang Sub Han, Md Ashraful Islam, Kyu Hwan Oh, Yeonwoong Jung

The authors review progress in manufacturing strategies for, and scientific working principles of, 2D TMD (transition metal dichalcogenide) heterolayers, material properties, and wafer-scale device applications. TMD semiconductors are highly promising because of their large mechanical resilience coupled with superior transport properties plus van der Waals attraction-enabled assembly. They discuss remaining challenges and prospects for improving quality of 2D TMD heterolayers in both material and manufacturing.

doi.org/10.1557/jmr.2020.27

In situ measurement of bulk modulus and yield response of glassy thin films via confined layer compression

Owen Brazil, Johann P. de Silva, Mithun Chowdhury, Heedong Yoon, Gregory B. McKenna, Warren C. Oliver, Jason Kilpatrick, John B. Pethica, Graham L.W. Cross

A novel means to measure thin-film mechanical properties based on flat punch indentation of a supported film with punch diameter many times the initial film thickness allows direct access to the intrinsic stress versus strain response and measurement of elastic modulus, bulk modulus, Poisson's ratio, and yield stress in a single loading curve. The authors demonstrate confined plastic yield for 170–470 nm thick polystyrene (PS), polymethyl-methacrylate, and amorphous selenium films on silicon, and the PS yield stress above Tg.

doi.org/10.1557/jmr.2020.42

High temperature organic electronics

Aristide Gumyusenge, Jianguo Mei

The authors address recent developments in organic semiconducting materials that can function at elevated temperatures using blends of semiconducting polymers with a thermally robust insulating matrix to form nanocomposites.

doi.org/10.1557/adv.2020.31

Comparison of neutral and charged polyelectrolyte bottlebrush polymers in dilute salt-free conditions

Alexandros Chremos, Ferenc Horkay

A comparison between molecular dynamics simulations and small-angle neutron scattering (SANS) experimental studies of two conditions of polymeric structures demonstrates the importance of charges on the polymer. Charged structures have a significantly larger radius of gyration than the neutral species. doi.org/10.1557/adv.2020.9

Showerhead-assisted chemical vapor deposition of perovskite films for solar cell application

S. Sanders, D. Stümmler, J.D. Gerber, J.H. Seidel, G. Simkus, M. Heuken, A. Vescan, H. Kalisch

The authors describe a processing tool that allows for large-area deposition of thin films for solar cell applications that, by controlling the gas-phase chemistry, provide phase pure iodide films.

doi.org/10.1557/adv.2020.126

Effect of production and curing conditions on the performance of stabilized compressed earth blocks: Kaolinite vs quartz-rich earthen material

Philbert Nshimiyimana, Hassan Seini Moussa, Adamah Messan, Luc Courard, African MRS

Construction materials using locally sourced materials provide a path to increased sustainability within emerging economies. The authors assess the properties of one such masonry material and compare the processing variables needed to provide suitable performance (and compressive strength properties) for a building application.

doi.org/10.1557/adv.2020.155