More Like this

1. Optical modeling of wide-bandgap perovskite and perovskite/silicon tandem solar cells using complex refractive indices for arbitrary-bandgap perovskite absorbers

   https://doi.org/10.1364/OE.26.027441  

   Manzoor, Salman ; Häusele, Jakob ; Bush, Kevin A. ; Palmstrom, Axel F. ; Carpenter, Joe ; Yu, Zhengshan J. ; Bent, Stacey F. ; Mcgehee, Michael D. ; Holman, Zachary C. ( October 2018 , Optics Express)
2. Ultrawide bandgap Al x Ga 1-x N channel heterostructure field transistors with drain currents exceeding 1.3 A/mm

   https://doi.org/10.35848/1882-0786/abb1c8  

   Gaevski, Mikhail ; Mollah, Shahab ; Hussain, Kamal ; Letton, Joshua ; Mamun, Abdullah ; Jewel, Mohi Uddin ; Chandrashekhar, MVS ; Simin, Grigory ; Khan, Asif ( October 2020 , Applied Physics Express)

   We report an Ultrawide Bandgap Al0.4Ga0.6N channel Metal-Oxide-Semiconductor Heterostructure field effect transistor with drain currents exceeding 1.33 A/mm (pulse) and 1.17A/mm (DC), around 2-fold increase over reported for AlGaN HFETs. The increase was achieved by incorporating hybrid barrier layer consisting of an AlN spacer, n-doped Al0.6Ga0.4N barrier and a thin reverse graded AlxGa1-xN (x from 0.60 to 0.30) cap layer. To enhance current spreading, a "perforated" channel layout comprising of narrow channel sections separated by current blocking islands was used. A composite ALD deposited ZrO2/Al2O3 film was used as gate dielectric. A breakdown field above 2MV/cm was measured. 

   more » « less
3. Suppressing material loss in the visible and near-infrared range for functional nanophotonics using bandgap engineering

   https://doi.org/10.1038/s41467-020-18793-y  

   Wang, Mingsong ; Krasnok, Alex ; Lepeshov, Sergey ; Hu, Guangwei ; Jiang, Taizhi ; Fang, Jie ; Korgel, Brian A. ; Alù, Andrea ; Zheng, Yuebing ( December 2020 , Nature Communications)

   null (Ed.)

   Abstract All-dielectric nanostructures have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts to the visible range is hindered by their larger absorption coefficient, thus encouraging the search for alternative dielectrics for nanophotonics. Here, we employ bandgap engineering to synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features for functional nanophotonics. We observe significant material loss suppression in a-Si:H NPs in the visible range caused by hydrogenation-induced bandgap renormalization, producing strong higher-order resonant modes in single NPs with Q factors up to ~100 in the visible and near-IR range. We also realize highly tunable all-dielectric meta-atoms by coupling a-Si:H NPs to photochromic spiropyran molecules. ~70% reversible all-optical tuning of light scattering at the higher-order resonant mode under a low incident light intensity is demonstrated. Our results promote the development of high-efficiency visible nanophotonic devices. 

   more » « less
4. Sustainable materials acceleration platform reveals stable and efficient wide-bandgap metal halide perovskite alloys

   https://doi.org/10.1016/j.matt.2023.06.040  

   Wang, Tonghui ; Li, Ruipeng ; Ardekani, Hossein ; Serrano-Luján, Lucía ; Wang, Jiantao ; Ramezani, Mahdi ; Wilmington, Ryan ; Chauhan, Mihirsinh ; Epps, Robert W. ; Darabi, Kasra ; et al ( September 2023 , Matter)

   The vast chemical space of emerging semiconductors, like metal halide perovskites, and their varied requirements for semiconductor applications have rendered trial-and-error environmentally unsustainable. In this work, we demonstrate RoboMapper, a materials acceleration platform (MAP), that achieves 10-fold research acceleration by formulating and palletizing semiconductors on a chip, thereby allowing high-throughput (HT) measurements to generate quantitative structure-property relationships (QSPRs) considerably more efficiently and sustainably. We leverage the RoboMapper to construct QSPR maps for the mixed ion FA 1-y Cs y Pb(I 1-x Br x ) 3 halide perovskite in terms of structure, bandgap, and photostability with respect to its composition. We identify wide-bandgap alloys suitable for perovskite-Si hybrid tandem solar cells exhibiting a pure cubic perovskite phase with favorable defect chemistry while achieving superior stability at the target bandgap of 1.7 eV. RoboMapper’s palletization strategy reduces environmental impacts of data generation in materials research by more than an order of magnitude, paving the way for sustainable data-driven materials research. 

   more » « less
5. Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe 2

   https://doi.org/10.1021/acsnano.2c01665  

   Yu, Yueyang ; Dong, Chuan-Ding ; Binder, Rolf ; Schumacher, Stefan ; Ning, Cun-Zheng ( March 2023 , ACS Nano)