The selection of either an oxidising or inert ambient during high temperature annealing is shown to affect dopant activation and electron–hole recombination in boron implanted silicon samples. Samples implanted with B at fluence between 3 × 1014 cm–2 to 3 × 1015 cm–2 are shown to have lower dopant activation after oxidation at 1000 °C compared to an equivalent anneal in an inert ambient. In addition, emitter recombination is shown to be up to 15 times higher after oxidation compared with an inert anneal for samples with equivalent passivation from deposited Al2O3 films. The observed increase in recombination for oxidised samples is attributed to the enhanced formation of boron‐interstitial defect clusters and dislocation loops under oxidising conditions. It is also shown that an inert anneal for 10 minutes at 1000 °C prior to oxidation has no significant impact on sheet resistance or recombination compared with a standard oxidation process.
A study on the effect of Mg doping in quantum‐well (QW) layers on dual‐wavelength light‐emitting diodes (LEDs) was performed. A series of dual‐wavelength LEDs with different Mg doping conditions were fabricated. According to electroluminescence measurement, as the Mg doping concentration and regions varied, improved hole distribution and bottom‐QW emission was achieved. This result is in accord with APSYS simulation. In addition, the sample with Mg doping in all QWs showed the highest output power and smallest efficiency droop. It is concluded that Mg doping in QWs could ameliorate the optical and electrical properties of dual‐wavelength LEDs. 相似文献
In thin film devices such as light‐emitting diodes, photovoltaic cells and field‐effect transistors, the processes of charge injection, charge transport, charge recombination, separation and collection are critical to performance. Most of these processes are relevant to nanoscale metal and metal oxide electrode–organic material interfacial phenomena. In this report we present a unique method for creating tailored one‐dimensional nanostructured silver, tin and/or zinc substituted indium oxide electrode structures over large areas. The method allows production of high aspect ratio nanoscale structures with feature sizes below 100 nm and a large range of dimensional tunability. We observed that both the electronic and optical properties of these electrodes are closely correlated to the nanostructure dimensions and can be easily tuned by control of the feature size. Surface area enhancement accurately describes the conductivity studies, while nanostructure dependent optical properties highlight the quasi‐plasmonic nature of the electrodes. Optimization of the nanostructured electrode transparency and conductivity for specific opto‐electronic systems is expected to provide improvement in device performance. 相似文献
The carrier transport in AlGaN light emission diode (LED) structures on Si‐substrates including an AlN multilayer (ML) buffer for reduction of defects was investigated using I–V‐characteristics and admittance spectroscopy. Additionally, AlN on Si ML and AlN/AlGaN:Si on Si structures were grown and analyzed separately. The AlN‐ML/AlGaN:Si heterojunction, and the pn‐junction including the AlGaN/GaN multi quantum well (MQW)‐structure were identified. As the main space charge regions (SCRs) controlling the carrier transport through the ultraviolet‐light emission diode (UV‐LED) structure the Si‐substrate/AlN‐ML heterojunctions pointed out. The I–V‐characteristic of the LED structure is described by the series resistance of the AlN‐ML and a parallel resistance with respect to the pn‐junction. Interface defect states and/or deep defects impact the series resistance. The carrier transport through the LED structure is controlled by a tunnel process described by a Fowler–Nordheim (FN)‐emission mainly through the AlN‐ML buffer forming the series resistance. 相似文献
