https://scholar.gist.ac.kr/handle/local/7919 2025-12-08T07:47:34Z https://scholar.gist.ac.kr/handle/local/25158 Title: 나노 단위의 압전전기장 조절을 통한 테라파 발진과 주파수 조절 Author(s): 정훈일; 정지훈; 이동선; C. J. Stanton; 조영달 2010-01-21T15:00:00Z https://scholar.gist.ac.kr/handle/local/15699 Title: ZnO/p-GaN Heterostructure for Solar Cells and the Effect of ZnGa2O4 Interlayer on Their Performance Author(s): Nam, Seung Yong; Choi, Yong Seok; Lee, Ju Ho; Park, Seong-Ju; Lee, Jeong Yong; Lee, Dong-Seon Abstract: We report the usage of ZnO material as an alternative for n-GaN for realizing III-nitride based solar cell. The fabricated solar cell shows large turn-on voltage of around 8 volts and a rapid decrease of photocurrent at low bias voltage under darkness and 1-sun illumination conditions, respectively. This phenomenon can be attributed to the formation of high-resistive ultra-thin layers at the ZnO/p-GaN junction interface during high temperature deposition. Transmission electron microscopy (TEM) studies carried out on the grown samples reveals that the ultra-thin layer consists of ZnGa2O4. It is found that the presence of insulating ZnGa2O4 film is detrimental in the performance of proposed heterostructure for solar cells. 2012-12-31T15:00:00Z https://scholar.gist.ac.kr/handle/local/32211 Title: Wafer-scale fabrication of memristive passive crossbar circuits for brain-scale neuromorphic computing Author(s): Choi, Sanghyeon; Bezugam, Sai Sukruth; Bhattacharya, Tinish; Kwon, Dongseok; Strukov, Dmitri B. Abstract: Memristive passive crossbar circuits hold great promise for neuromorphic computing, offering high integration density combined with massively parallel operation. However, scaling up the integration complexity of such circuits remains challenging due to low device yield, stemming from the intrinsic properties of filamentary switching and limitations in current crossbar fabrication technologies. Here, we report a scalable passive crossbar device technology achieved through a co-design approach for memristors and crossbar structures. The proposed hardware platform is fabricated using CMOS-compatible processes without complex and high-temperature steps, enabling high device yield along with reliable and multibit operation. Importantly, the fabrication process is successfully scaled to a 4-inch wafer, maintaining an average device yield (>similar to 95%) and preserving key switching characteristics. The potential of this platform is showcased by implementing image classification of the fashion MNIST benchmark with an ex-situ trained spiking neural network. We believe that our work represents a significant step toward brain-scale neuromorphic computing systems. 2025-09-30T15:00:00Z https://scholar.gist.ac.kr/handle/local/13936 Title: Very thin ITO/metal mesh hybrid films for a high-performance transparent conductive layer in GaN-based light-emitting diodes Author(s): Min, Jung-Hong; Kwak, Hoe-Min; Kim, Kiyoung; Jeong, Woo-Lim; Lee, Dong-Seon Abstract: In this paper, we introduce very thin Indium tin oxide (ITO) layers (5, 10, and 15 nm) hybridized with a metal mesh to produce high-performance transparent conductive layers (TCLs) in near-ultraviolet light-emitting diodes (NUV LEDs). Using UV-vis-IR spectrometry, Hall measurement, and atomic force microscopy, we found that 10 nm was the optimal thickness for the very thin ITO layers in terms of outstanding transmittance and sheet resistance values as well as stable contact properties when hybridized with the metal mesh. The proposed layers showed a value of 4.56 Omega/square, for sheet resistance and a value of 89.1% for transmittance. Moreover, the NUV LEDs fabricated with the hybrid TCLs achieved similar to 140% enhanced light output power compared to that of 150 nm thick ITO layers. Finally, to verify the practical usage of the TCLs for industrial applications, we packaged the NUV LED chips and obtained improved turn-on voltage (3.48 V) and light output power (similar to 116%) performance. 2016-12-31T15:00:00Z