Gao Yunzhi, Liu Xiaofeng, Hu Wei, Yang Jinlong
Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Phys Chem Chem Phys. 2020 Jun 21;22(23):12973-12979. doi: 10.1039/d0cp01484b. Epub 2020 Jun 8.
Palladium diselenide (PdSe) is a two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductor with desirable properties for nanoelectronics. Here, we demonstrate that 2D layered PdSe adsorbed with two kinds of organic molecules, an electrophilic molecule tetracyano-p-quinodimethane (TCNQ) as an electron acceptor and a nucleophilic molecule tetrathiafulvalene (TTF) as an electron donor, can realize tunable p-type and n-type doping of 2D PdSe by using first-principles density functional theory (DFT) calculations. We find that TCNQ attracts electrons from PdSe and introduces shallow acceptor states close to the valence band edge, resulting in p-type doping of PdSe, while TTF donates electrons into PdSe and introduces shallow donor states close to the conduction band edge, resulting in n-type doping of PdSe. Furthermore, such p-type and n-type doping of PdSe can be efficiently controlled with an external electric field, interlayer distance and substrate thickness. Such effective bipolar doping of PdSevia molecular adsorption would broaden its applications in nanoelectronics.
二硒化钯（PdSe₂）是一种二维（2D）过渡金属二硫属化物（TMD）半导体，具有适用于纳米电子学的理想特性。在此，我们证明，通过第一性原理密度泛函理论（DFT）计算，吸附有两种有机分子的二维层状PdSe₂，即作为电子受体的亲电分子四氰基对苯二醌二甲烷（TCNQ）和作为电子供体的亲核分子四硫富瓦烯（TTF），可以实现二维PdSe₂的可调p型和n型掺杂。我们发现，TCNQ从PdSe₂吸引电子，并在价带边缘附近引入浅受主态，导致PdSe₂的p型掺杂，而TTF向PdSe₂提供电子，并在导带边缘附近引入浅施主态，导致PdSe₂的n型掺杂。此外，通过外部电场、层间距离和衬底厚度，可以有效地控制PdSe₂的这种p型和n型掺杂。通过分子吸附对PdSe₂进行如此有效的双极掺杂将拓宽其在纳米电子学中的应用。
