김은규 교수

The formation of a dense and uniform thin layer on the substrates is crucial for the fabrication of high-performance perovskite solar cells (PSCs) containing formamidinium with multiple cations and mixed halide anions. The concentration of defect states, which reduce a cell's performance by decreasing the open-circuit voltage and short-circuit current density, needs to be as low as possible. We show that the introduction of additional iodide ions into the organic cation solution, which are used

The light‐harvesting Sb 2 S 3 surface on mesoporous‐TiO 2 in inorganic–organic heterojunction solar cells is sulfurized with thioacetamide (TA). The photovoltaic performances are compared before and after TA treatment, and the state of the Sb 2 S 3 is investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, and deep‐level transient spectroscopy (DLTS). Although there are no differences in crystallinity and composition, the TA‐treated solar cells exhibit significantly enhanced perform

We demonstrated p-type conduction in MoS2 grown with phosphorous pentoxide via chemical vapor deposition (CVD). Monolayer MoS2 with a triangular shape and 15-µm grains was confirmed by atomic force microscopy. The difference between the Raman signals of the A1g and E12g modes for both the pristine and P-doped samples was 19.4 cm−1. In the X-ray photoelectron spectroscopy results, the main core level peaks of P-doped MoS2 downshifted by about 0.5 eV to a lower binding energy compared to the prist

at room temperature, are realized by quantum-mechanical tunneling of majority and minority carriers across the barrier. These carristors have a potential application as the fundamental building block of low-power consumption electronics.

Abstract Next-generation flexible and transparent electronics demand newer materials with superior characteristics. Tin dichalcogenides, Sn(S,Se) 2 , are layered crystal materials that show promise for implementation in flexible electronics and optoelectronics. They have band gap energies that are dependent on their atomic layer number and selenium content. A variety of studies has focused in particular on tin disulfide (SnS 2 ) channel transistors with conventional silicon substrates. However,

Molybdenum disulfide (MoS₂) film fabricated by a liquid exfoliation method has significant potential for various applications, because of its advantages of mass production and low-temperature processes. In this study, residue-free MoS₂ thin films were formed during the liquid exfoliation process and their electrical properties were characterized with an interdigitated electrode. Then, the MoS₂ film thickness could be controlled by centrifuge condition in the rang

Abstract We have optimized the responsivity and response speed of a β -Ga 2 O 3 -based photodetector. The β -Ga 2 O 3 thin films were deposited on a glass substrate under various oxygen partial pressures from 0 to 50 mTorr using pulsed laser deposition. Time-response measurements show that the as-grown β -Ga 2 O 3 at an oxygen partial pressure of 50 mTorr has the fastest response speed and decay times of 33 and 100 ms, which are better than those prepared at lower oxygen pressures. This sample a

Transition metal dichalcogenides (TMDs) benefit electrical devices with spin–orbit coupling and valley- and topology-related properties. However, TMD-based devices suffer from traps arising from defect sites inside the channel and the gate oxide interface. Deactivating them requires independent treatments, because the origins are dissimilar. This study introduces a single treatment to passivate defects in a multilayer MoS 2 FET. By applying back-gate bias, protons from an H–TFSI droplet are inje