김병성 교수

We report metal-free synthesis of high-density single-crystal elementary semiconductor nanowires with tunable electrical conductivities and systematic diameter control with narrow size distributions. Single-crystal silicon and germanium nanowires were synthesized by nucleation on nanocrystalline seeds and subsequent one-dimensional anisotropic growth without using external catalyst. Systematic control of the diameters with tight distribution and tunable doping concentration were realized by adju

Hybrid colloidal quantum dot (CQD) solar cells are fabricated from multilayer stacks of lead sulfide (PbS) CQD and single layer graphene (SG). The inclusion of graphene interlayers is shown to increase power conversion efficiency by 9.18%. It is shown that the inclusion of conductive graphene enhances charge extraction in devices. Photoluminescence shows that graphene quenches emission from the quantum dot suggesting spontaneous charge transfer to graphene. CQD photodetectors exhibit increased p

We investigate time-dependent inorganic ligand exchanging effect and photovoltaic performance of lead sulfide (PbS) nanocrystal films. With optimal processing time, volume shrinkage induced by residual oleic acid of the PbS colloidal quantum dot (CQD) was minimized and a crack-free film was obtained with improved flatness. Furthermore, sufficient surface passivation significantly increased the packing density by replacing from long oleic acid to a short iodide molecule. It thus facilities excito

Electronic devices in highly integrated and miniaturized systems demand electromagnetic interference shielding within nanoscale dimensions. Although several ultrathin materials have been proposed, satisfying various requirements such as ultrathin thickness, optical transparency, flexibility, and proper shielding efficiency remains a challenge. Herein, we report an ultrahigh electromagnetic interference (EMI) SSE/<i>t</i> value (>10⁶ dB cm²/g) using a conductive CuS nanoshee

A Pixel-based sub-resolution assist feature (SRAF) insertion technique has been considered as one of the promising solutions by maximizing the common process window. However, process window improvement of the pixel-based SRAF technique is limited by the simplification of SRAFs for mask manufacturability. Mask simplification and mask rule check (MRC) constraints parameters for pixel-based SRAF technique are the critical factors for mask production without a big loss of its benefit. In this study,

The contrast curve of positive and negative electron-beam resists such as polymethylmethacrylate (PMMA), ZEP520A, and hydrogen silsesquioxane (HSQ) at 200 kV electron-beam was estimated by using continuous slow down approximation (CSDA) model with both non-relativistic and relativistic Bethe stopping power. Experimental results show that simple CSDA model well explains the overall response of these various electron-beam resists to high energy electron-beam only if we use the relativistic Bethe s

We report on the catalytic growth of thin carbon sheathed single crystal germanium nanowires (GeNWs), which can solve the obstacles that have disturbed a wide range of applications of GeNWs. Single crystal Ge NW core and amorphous carbon sheath are simultaneously grown via vapor-liquid-solid (VLS) process. The carbon sheath completely blocks unintentional vapor deposition on NW surface, thus ensuring highly uniform diameter, dopant distribution, and electrical conductivity along the entire NW le

This report analyzes the benefits obtained through Back-Side Interconnect (BSI) technology, encompassing Back-Side Power Delivery Network (BSPDN) and Back-Side Signal (BSS), from the perspective of Design-Technology Co-Optimization (DTCO). Through BSPDN, benefits such as metal pitch relaxation and/or cell height reduction can be achieved. Additionally, the implementation of BSS technology allows for intra-cell and inter-cell routing on the back side, leading to improved speed and greater reducti

We report a direct growth of highly conductive nanocrystalline graphene on dielectric SiO2 nanowires. Graphene structure on the nanowire surface is easily controlled by adjusting the growth conditions. In addition, highly dense ZnO nanorods are electrochemically grown on graphene/dielectric nanowire, which demonstrates potential for the nanostructured electrode with controlled morphology.

The roll-to-roll (R2R) gravure process has the potential for manufacturing single-wall carbon nanotubes (SWCNT)-based thin film transistor (TFT) arrays on a flexible plastic substrate. A significant hurdle toward the commercialization of the R2R-printed SWCNT-TFT array is the lack of a suitable, simple, and rapid method for measuring the uniformity of printed products. We developed a probing instrument for characterizing R2R gravure printed TFT, named PICR2R-TFT, for rapidly characterizing R2R-p

The parasitic elements for HEMTs are extracted using an iterative technique based on the exact solution of the channel transmission equation. The proposed method uses two-point S-parameter measurements under pinched FET and normal operating gate bias conditions without hot bias measurements. Convergence is stable and the results are reliable.

Carbon-containing alloy materials such as Ge(1-x)C(x) are attractive candidates for replacing silicon (Si) in the semiconductor industry. The addition of carbon to diamond lattice not only allows control over the lattice dimensions, but also enhances the electrical properties by enabling variations in strain and compositions. However, extremely low carbon solubility in bulk germanium (Ge) and thermodynamically unfavorable Ge-C bond have hampered the production of crystalline Ge(1-x)C(x) alloy ma

Cold FET methods have been widely used for active FET modeling assuming the bias independence of parasitic elements. However, the assumption has been merely justified by the resulting modeling accuracy. This paper investigates the consistency of cold FET conditions with active FET through the exact and the error minimizing solutions of cold FET intrinsic reference plane constrained by the feedback condition of active FET model. Additionally, drain bias dependence of parasitic resistances will be

Sub-resolution assist features (SRAFs) have been used to enhance lithographic process window of main features. As the device is scaled down, the SRAF size decreases drastically and the distance between main features and SRAF closes up. The variation of main feature CD and SRAF size from mask production process influences destructively on gate CD control and it makes the device performance degraded. Fabrication of small and uniform-sized SRAFs is one of the key mask technologies because mean-to-t