金属—载体强相互作用（SMSI）对Pd／ZnO半导体陶瓷气敏特性的作用

本文借助XRD,红外光谱等分析手段,研究了金属-载体相互作用状态对Pd/ZnO半导体陶瓷气敏特性的影响,据此提出贵金属催化剂和半导体陶瓷在气敏特性中的共同作用机理。PdZn界面层是氢处理时半导体正离子和金属原子间的相互扩散及反应所致。可以认为金属-载体间的强相互作用(SMSI)能显著提高其气敏特性。     

Current-voltage studies on β-FeSi2/Si heterojunction

I-V characteristics of both β-FeSi₂/n-Si and β-FeSi₂/p-Si were studied at room temperature. The junctions were formed by depositing Fe on Si selectively followed by thermal annealing and some samples were later treated by pulsed laser. Temperature of thermal annealing and diode area were also varied.I-V studies on all these samples were done and ideality factors were computed. Results obtained were interpreted. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore.     

Poly(arylenethynyl-thienoacenes) as candidates for organic semiconducting materials. A DFT insight

The conducting properties for holes and electrons of a set of 16 poly(arylenethynyl-thienoacene) derivatives as candidates for organic semiconductors have been theoretically studied at density functional theory (DFT) level. Some of the selected compounds show adequate values of charge carrier mobilities and injection parameters to be considered either p- or n-type organic semiconductors, although they all show high LUMO energy levels as compared to the Fermi level of Au electrode, decreasing their feasibility as ambipolar semiconductors. Derivatization with electron withdrawing moieties (F and CN) permits to suggest some of the studied compounds to display balanced both ease charge injection and high charge mobilities for holes and electrons, which could allow high performances as ambipolar semiconductors.     

“模拟电路”课程器件级实验改革探索

模拟电路是电子信息类专业本科生的核心专业基础课程。课程中的内容涉及较多抽象概念,导致学生在理解和掌握上存在困难。通过让学生亲手测试相关器件的参数,能帮助学生更好理解抽象概念。但是,目前实验主要集中在电路,缺乏PN结和场效应晶体管等器件的实验测试条件。针对这一问题,提出利用基于二维半导体材料的PN结和场效应晶体管用于课程实验,加深学生对所学知识的理解和掌握。     

Morphological and dielectric changes of XLPE insulation due to thermal aging

Transmission power cables are heated by conductor current. The morphology of the XLPE insulation may be changed by thermal aging. Disk-shaped insulating materials with semiconductive electrodes were used to understand this thermal effect against the dielectric breakdown strengths. The disk specimens were aged at 80 and 100°C before the breakdown strength measurements. These results showed that the dielectric breakdown strengths were improved with aging time. Analytical investigation of the insulating materials indicated that there were morphological changes such as increases of the lamella thickness and the spherulite diameter and decrease of the averaged lamella angle through heating. Cable specimens aged thermally with the same condition as the risk specimens also were observed with similar morphological changes in the insulation. Therefore it is concluded that the promotion of the crystallization by thermal aging is effective in improving the breakdown strength of the XLPE insulation unless it causes extreme deterioration.     

Improved efficiency in semiconducting polymer light-emitting diodes

We report visible light emission from metal-polymer diodes made from semiconducting polymers, with indium-tin oxide as the “ohmic” contact, and a variety of metals as the barrier metal. Our results, which confirm the discovery by the Cambridge group [Nature347, 539 (1990)], demonstrate that light-emitting diodes can be fabricated by casting the polymer film on indium-tin oxide from solution with no subsequent polymer processing or heat treatment required. Electrical characterization reveals diode behavior with rectification ratios greater than 10⁵ at sufficiently high voltages. Use of an electrode material with low work function leads to more than an order of magnitude improvement in the room-temperature efficiency of the devices. For example, the most efficient devices made with calcium as the rectifying contact display efficiencies of 0.01 photons per electron.