Palladium (Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics and optoelectronics. However, the synthesis of large-scale uniform PdS and PdS₂ nanofilms (NFs) remains an enormous challenge. In this work, 2-inch wafer-scale PdS and PdS₂ NFs with excellent stability can be controllably prepared via chemical vapor deposition combined with electron beam evaporation technique. The thickness of the pre-deposited Pd film and the sulfurization temperature are critical for the precise synthesis of PdS and PdS₂ NFs. A corresponding growth mechanism has been proposed based on our experimental results and Gibbs free energy calculations. The electrical transport properties of PdS and PdS₂ NFs were explored by conductive atomic force microscopy. Our findings have achieved the controllable growth of PdS and PdS₂ NFs, which may provide a pathway to facilitate PdS and PdS₂ based applications for next-generation high performance optoelectronic devices.

We have prepared the graphene/MoS2 heterostructure by a hydrothermal method, and presented its nonlinear absorption parameters and application as a nonlinear optical modulator in the mid-infrared region. Using the nonlinear optical modulator, stable passively Q-switched operation of an Er3+-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber laser at ～2.8 μm can be obtained. The Q-switched Er3+-doped ZBLAN fiber laser can yield per-pulse energy up to 2.2 μJ with the corresponding pulse width and pulse repetition rate of 1.9 μs and 45 kHz, respectively. Our results indicate that the graphene/MoS2 heterostructure can be a robust optical modulator for pulsed lasers in the mid-infrared spectral range.