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1. Gate‐Tunable Photoresponse Time in Black Phosphorus–MoS ₂ Heterojunctions

   https://doi.org/10.1002/adom.201800832  

   Walmsley, Thayer_S; Chamlagain, Bhim; Rijal, Upendra; Wang, Tianjiao; Zhou, Zhixian; Xu, Ya‐Qiong (December 2018, Advanced Optical Materials)

   Abstract Gate‐/wavelength‐dependent scanning photocurrent measurements of black phosphorous (BP)–MoS₂heterojunctions have shown that the Schottky barrier at the MoS₂–metal interface plays an important role in the photoresponse dynamics of the heterojunction. When the Fermi level is close to the conduction band of MoS₂, photoexcited carriers can tunnel through the narrow depletion region at the MoS₂–metal interface, leading to a short response time of 13 µs regardless of the incident laser wavelength. This response speed is comparable or better than that of other few‐layer BP–MoS₂heterojunctions. Conversely, when the MoS₂channel is in the off‐state, the resulting sizeable Schottky barrier and depletion width make it difficult for photoexcited carriers to overcome the barrier. This significantly delays the carrier transit time and thus the photoresponse speed, leading to a wavelength‐dependent response time since the photoexcited carriers induced by short wavelength photons have a higher probability to overcome the Schottky barrier at the MoS₂–metal interface than long wavelength photons. These studies not only shed light on the fundamental understanding of photoresponse dynamics in BP–MoS₂heterojunctions, but also open new avenues for engineering the interfaces between 2D materials and metal contacts to reduce the response time of 2D optoelectronics. 

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2. Efficient hole transfer from monolayer WS ₂ to ultrathin amorphous black phosphorus

   https://doi.org/10.1039/C8NH00234G  

   Bellus, Matthew Z.; Yang, Zhibin; Zereshki, Peymon; Hao, Jianhua; Lau, Shu Ping; Zhao, Hui (January 2019, Nanoscale Horizons)

   The newly developed van der Waals materials allow fabrication of multilayer heterostructures. Early efforts have mostly focused on heterostructures formed by similar materials. More recently, however, attempts have been made to expand the types of materials, such as topological insulators and organic semiconductors. Here we introduce an amorphous semiconductor to the material library for constructing van der Waals heterostructures. Samples composed of 2 nm amorphous black phosphorus synthesized by pulsed laser deposition and monolayer WS 2 obtained by mechanical exfoliation were fabricated by dry transfer. Photoluminescence measurements revealed that photocarriers excited in WS 2 of the heterostructure transfer to amorphous black phosphorus, in the form of either energy or charge transfer, on a time scale shorter than the exciton lifetime in WS 2 . Transient absorption measurements further indicate that holes can efficiently transfer from WS 2 to amorphous black phosphorus. However, interlayer electron transfer in either direction was found to be absent. The lack of electron transfer from amorphous black phosphorus to WS 2 is attributed to the localized electronic states in the amorphous semiconductor. Furthermore, we show that a hexagonal BN bilayer can effectively change the hole transfer process. 

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3. Tuning the electronic properties of the γ-Al ₂ O ₃ surface by phosphorus doping

   https://doi.org/10.1039/C9CP03105G  

   Acikgoz, Muhammed; Khoshi, M. Reza; Harrell, Jaren; Genova, Alessandro; Chawla, Rupali; He, Huixin; Pavanello, Michele (July 2019, Physical Chemistry Chemical Physics)

   Tuning the electronic properties of oxide surfaces is of pivotal importance, because they find applicability in a variety of industrial processes, including catalysis. Currently, the industrial protocols for synthesizing oxide surfaces are limited to only partial control of the oxide's properties. This is because the ceramic processes result in complex morphologies and a priori unpredictable behavior of the products. While the bulk doping of alumina surfaces has been demonstrated to enhance their catalytic applications ( i.e. hydrodesulphurization (HDS)), the fundamental understanding of this phenomenon and its effect at an atomic level remain unexplored. In our joint experimental and computational study, simulations based on Density Functional Theory (DFT), synthesis, and a variety of surface characterization techniques are exploited for the specific goal of understanding the structure–function relationship of phosphorus-doped γ-Al 2 O 3 surfaces. Our theoretical calculations and experimental results agree in finding that P doping of γ-Al 2 O 3 leads to a significant decrease in its work function. Our computational models show that this decrease is due to the formation of a new surface dipole, providing a clear picture of the effect of P doping at the surface of γ-Al 2 O 3 . In this study, we uncover a general paradigm for tuning support–catalyst interactions that involves electrostatic properties of doped γ-Al 2 O 3 surface, specifically the surface dipole. Our findings open a new pathway for engineering the electronic properties of metal oxides’ surfaces. 

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4. Structural Investigation of Silver Vanadium Phosphorus Oxide (Ag ₂ VO ₂ PO ₄ ) and Its Reduction Products

   https://doi.org/10.1021/acs.chemmater.1c00446  

   Sun, He; Hammann, Blake A.; Brady, Alexander B.; Singh, Gurpreet; Housel, Lisa M.; Takeuchi, Esther S.; Takeuchi, Kenneth J.; Marschilok, Amy C.; Hayes, Sophia E.; Szczepura, Lisa F. (June 2021, Chemistry of Materials)

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5. Sol Gel-Based Synthesis of the Phosphorus-Containing MAX Phase V ₂ PC

   https://doi.org/10.1021/acs.inorgchem.2c02880  

   Sinclair, Jordan; Siebert, Jan P.; Juelsholt, Mikkel; Shen, Chen; Zhang, Hongbin; Birkel, Christina S. (October 2022, Inorganic Chemistry)