RESUMEN
Due to its portable and self-powered characteristics, the construction of Ga2O3-based semiconductor flexible devices that can improve the adaptability in various complex environments have drawn great attention in recent decades. However, conventional Ga2O3-based flexible heterojunctions are based on either amorphous or poor crystalline Ga2O3 materials, which severely limit the performance of the corresponding devices. Here, through lattice-symmetry and energy-band alignment engineering, we construct a high-quality crystalline flexible NiO/ß-Ga2O3 p-n self-powered photodetector. Owing to its suitable energy-band alignment structure, the device shows a high photo-to-dark current ratio (1.71 × 105) and a large detection sensitivity (6.36 × 1014 Jones) under zero bias, which is superior than most Ga2O3 self-powered photodetectors even for those based on rigid substrates. Moreover, the fabricated photodetectors further show excellent mechanical stability and robustness in bending conditions, demonstrating their potential practical applications in flexible optoelectronic devices. These findings provide insights into the manipulation of crystal lattice and energy band engineering in flexible self-powered photodetectors and also offer guideline for designing other Ga2O3-based flexible electronic devices.
RESUMEN
Wearable and flexible ß-Ga2O3-based semiconductor devices have attracted considerable attention, due to their outstanding performance and potential application in real-time optoelectronic monitoring and sensing. However, the unavailability of high-quality crystalline and flexible ß-Ga2O3 membranes limits the fabrication of relevant devices. Here, through lattice epitaxy engineering together with the freestanding method, we demonstrate the preparation of a robust bending-resistant and crystalline ß-Ga2O3 (-201) membrane. Based on this, we fabricate a flexible ß-Ga2O3 photodetector device that shows comparable performance in photocurrent responsivity and spectral selectivity to conventional rigid ß-Ga2O3 film-based devices. Moreover, based on the transferred ß-Ga2O3 membrane on a silicon wafer, the PEDOT:PSS/ß-Ga2O3 p-n heterojunction device with self-powered characteristic was constructed, further demonstrating its superior heterogeneous integration ability with other functional materials. Our results not only demonstrate the feasibility of obtaining a high-quality crystalline and flexible ß-Ga2O3 membrane for an integrated device but also provide a pathway to realize flexible optical and electronic applications for other semiconducting materials.
RESUMEN
Despite being highly promising for applications in emergent electronic devices, decoding both the ion-electron-lattice coupling in correlated materials at the atomic scale and the electronic band structure remains a big challenge due to the strong and complex correlation among these degrees of freedom. Here, taking an epitaxial thin film of perovskite nickelate NdNiO3 as a model system, hydrogen-ion-induced giant lattice distortion and enhanced NiO6 octahedra tilting/rotation are demonstrated, which leads to a new robust hydrogenated HNdNiO3 phase with lattice expansion larger than 10% on a series of substrates. Moreover, under the effect of ion-electron synergistic doping, it is found that the proposed electronic antidoping, i.e., the doped electrons mainly fill the ground-state oxygen 2p holes instead of changing the Ni oxidation state from Ni3+ to Ni2+ , dominates the metal-insulator transition. Meanwhile, lattice modification with enhanced Ni-O-Ni bond tilting or rotation mainly modifies the orbital density of states near the Fermi level. Last, by electric-field-controlled hydrogen-ion intercalation and its strong coupling to the lattice and electron charge, selective micrometer-scale patterns with distinct structural and electronic states are fabricated. The results provide direct evidence for a strong ion-electron-lattice coupling in correlated physics and exhibit its potential applications in designing novel materials and devices.
RESUMEN
Ionic liquid gating (ILG) that drives the ions incorporate into or extract from the crystal lattice, has emerged as a new pathway to design materials. Although many intriguing emergent phenomena, novel physical properties and functionalities have been obtained, the gating mechanism governing the ion and charge transport remains unexplored. Here, by using the model system of brownmillerite SrCoO2.5 and the corresponding electric-field controlled tri-state phase transformation among the pristine SrCoO2.5, hydrogenated HSrCoO2.5 and oxidized perovskite SrCoO3-δ through the dual ion switch, the ionic diffusion and electronic transport processes were carefully investigated. Through controlling gating experiment by design, we find out that the collaborative interaction between charge transport and ion diffusion plays an essential role to prompt the hydrogen or oxygen ions incorporate into the crystal lattice of SrCoO2.5, and therefore leading to formation of new phases. At region closer to the electrode, the electron can shuttle more readily in (out) the material, correspondingly the incorporation of hydrogen (oxygen) ions and phase transformation is largely affiliated. With the compensated charge of electron as well as the reaction front gradually moving away from the electrode, the new phases would be developed successively across the entire thin film. This result unveils the underlying mechanism in the electric-field control of ionic incorporation and extraction, and therefore provides important strategy to achieve high efficient design of material functionalities in complex oxide materials.
