https://scholar.dgist.ac.kr/handle/20.500.11750/241 2026-08-05T16:34:19Z https://scholar.dgist.ac.kr/handle/20.500.11750/60454 Title: High-Gain Ag2Te/MoS2 Hybrid Photodetectors for Short-Wave Infrared Imaging Author(s): Jeong, Seock-Jin; Ko, Hyun Woo; Jo, Suyeon; Selvaraj, Joicy; Kim, Jung-Min; Lee, Namji; Ahn, Jae-Hyeon; Lee, Hyeonchae; Jeong, Seungmin; Kim, Heedae; Seo, Paul Hongsuck; Shim, Jae Won; Kim, Yonghun; Ra, Hyun-Soo; Park, Min-Chul; Lee, Jong-Soo Abstract: Physical artificial intelligence has emerged as a pivotal component in next-generation humanoid technologies, including advanced optical sensors, as it enables autonomous acquisition of sensory information. This study reports a high-performance 0D/2D hybrid photodetector using a high-gain Ag2Te/MoS2 hybrid structure for visible to short-wave infrared (SWIR) photodetection, achieved by the absorption of Ag2Te quantum dots in the infrared region (similar to 1450 nm). The Ag2Te/MoS2 photodetector exhibits a high photoresponsivity of around 7.5 & times; 105 AW-1 and a specific detectivity of over 9.9 & times; 108 Jones at 1 & micro;W/cm2 illumination power with a 0.2 V drain bias voltage. Furthermore, depending on the gain of the photodetector, a fast response speed can also be achieved, with rise and decay times as short as 13 and 23 ms. The 0D/2D hybrid devices were successfully implemented in a 32 & times; 32 array format for infrared imaging, with the results demonstrating spatially resolved pattern reconstruction and real-time photoresponse acquisition. By hybridizing quantum dots and 2D materials, the developed photodetector has broad potential applications, including use in highly integrated SWIR image sensors. 2026-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60453 Title: Electrically Tunable Tunneling and Spectral Response in WSe2/h-BN/CdSe/Graphene Heterostructure Author(s): Lee, Sang-Hyeon; Teku, Justice Agbeshie; Jeong, Min-Hye; Ahn, Jae-Hyeon; Chae, Weon-Sik; Kwak, Do-Hyun; Lee, Jong-Soo Abstract: Mixed-dimensional heterostructures consisting of zero- and two-dimensional materials offer a promising platform for optoelectronic devices, as the versatility of material combination allows tunable optical properties. Bias-induced approaches provide an additional means to tune the optical properties beyond the intrinsic band alignment of van der Waals junctions. Here, bias-induced tunneling characteristics are achieved in vertically stacked WSe2/h-BN/CdSe quantum dots/graphene heterostructures by employing the top graphene electrode to regulate carrier transport across the h-BN barrier. The electrical analyses based on the Simmons approximation demonstrate tunneling-mediated charge transfer through thin h-BN layers and bias-dependent modulation of the barrier height. Furthermore, tunneling-induced exciton dissociation in WSe2 and CdSe QDs is observed through spectral responsivity and scanning photocurrent measurements. This work establishes a voltage-dependent tunneling platform that enables deterministic control of carrier dynamics in mixed-dimensional optoelectronic devices. 2026-05-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60215 Title: Advances in Photopatterning of Quantum Dots: Mechanisms, Materials, and Device Applications Author(s): Lee, Namji; Taylor Derrick Allan; Choi, Donghyun; Kwak, Do-Hyun; Lee, Jong-Soo Abstract: The precise patterning of quantum dots (QDs) is crucial for integrating advanced optoelectronic devices, including quantum dot light-emitting diodes (QLEDs) and photodetectors. However, conventional patterning techniques often suffer from poor film uniformity and degradation of the optical and electronic properties of QDs. Recently, direct optical lithography has emerged as a powerful alternative, enabling high-resolution patterning while better preserving QD integrity. In this review, we summarize the representative photopatterning mechanisms, including ligand exchange, ligand cross-linking, ligand decomposition, and ligand desorption and discuss the associated material considerations, including QDs, surface ligands, and charge-transport layers. We further highlight recent breakthroughs in applying these strategies to QLEDs and photodetectors. Finally, we outline the remaining challenges - including solubility control, industrial scalability, photodamage mitigation, and the optimization of processing conditions - and propose potential strategies for enhancing patterning quality, device performance, and manufacturability. 2026-01-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59986 Title: Thick ZnS Shells on CsPbBr3Quantum Dots by Colloidal-Atomic Layer Deposition for Enhanced Photoluminescence and Stability Author(s): Teku, Justice Agbeshie; Taylor, Derrick Allan; Lee, Jong-Soo Abstract: The colloidal-atomic layer deposition (c-ALD) method is employed to grow a zinc sulfide (ZnS) shell on CsPbBr3 perovskite quantum dots (PeQDs) to form CsPbBr3/ZnS core/shell heterostructures to address the intrinsic stability challenges of PeQDs. The c-ALD process offers layer by layer control over the thickness of the shell, enabling uniform and conformal encapsulation, which significantly passivates the surface defects and enhances the optical properties of the PeQDs. This approach significantly improves photoluminescence quantum yield, increases environmental stability, and prolongs the average radiative lifetime of the CsPbBr3 PeQDs. The structural and spectroscopic analysis confirms the formation of a thick and uniform ZnS shell. Furthermore, the resulting core/shell PeQDs exhibit exceptional thermal, photostability, and aqueous durability, surpassing the limitations of pristine CsPbBr3 PeQDs. This work opens new opportunities for the c-ALD method to be integrated into perovskite core/shell heterostructures for advancing optoelectronic technologies. 2025-07-31T15:00:00Z