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Characteristic improvements of thin film AlGaInP red light emitting diodes on a metallic substrate
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We report a type of thin film Al Ga In P red light emitting diode(RLED) on a metallic substrate by electroplating copper(Cu) to eliminate the absorption of Ga As grown substrate.The fabrication of the thin film RLED is presented in detail.Almost no degradations of epilayers properties are observed after this substrate transferred process.Photoluminescence and electroluminescence are measured to investigate the luminous characteristics.The thin film RLED shows a significant enhancement of light output power(LOP) by improving the injection efficiency and light extraction efficiency compared with the reference RLED on the Ga As parent substrate.The LOPs are specifically enhanced by 73.5% and 142% at typical injections of 2 A/cm~2 and 35 A/cm~2 respectively from electroluminescence.Moreover,reduced forward voltages,stable peak wavelengths and full widths at half maximum are obtained with the injected current increasing.These characteristic improvements are due to the Cu substrate with great current spreading and the back reflection by bottom electrodes.The substrate transferred technology based on electroplating provides an optional way to prepare high-performance optoelectronic devices,especially for thin film types. 相似文献
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Effect of Dopant Concentration in a Base Layer on Photocurrent——Voltage Characteristics of Photovoltaic Power Converters
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It is known that the p–n junction of an absorption region is a crucial part for power conversion efficiency of photovoltaic power converters. We fabricate four samples with different dopant concentrations in base layers.The dependences of power conversion efficiency and fill factor on input power are displayed by photocurrent–voltage measurement. Photoluminescence characteristics under open circuit and connected circuit conditions are also studied. It is found that the status of p–n junction mat... 相似文献
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以螺旋型抗菌肽HPRP-A1为模板,利用精氨酸(R)对HPRP-A1序列中的赖氨酸(K)进行不同位点、不同数量的取代,结合改造前后抗菌肽的螺旋度、疏水性及自聚集常数等理化性质,研究了螺旋型抗菌肽结构与活性的相关性.进一步结合脂质体模拟和细胞膜穿透实验,对螺旋型抗菌肽与不同类型细胞膜的相互作用过程进行了研究.结果表明,增加精氨酸的取代数量,会增强抗菌肽的疏水性和螺旋度,导致螺旋型抗菌肽对真核细胞的毒性增强;但精氨酸的增加会伴随着抗菌肽自聚集能力的降低以及抗菌肽对细菌细胞膜的渗透性降低,导致抗菌肽的抗菌活性降低.本研究对于设计和改造具有应用前景的螺旋型抗菌肽具有重要指导意义. 相似文献
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We have successfully prepared GaN based high electron mobility transistors(HEMTs)on metallic substrates transferred from silicon substrates by electroplating technique.GaN HEMTs on Cu substrates are demonstrated to basically have the same good electric characteristics as the chips on Si substrates.Furthermore,the better heat dissipation of HEMTs on Cu substrates compared to HEMTs on Si substrates is clearly observed by thermoreflectance imaging,showing the promising potential for very high-power and high-temperature operation.This work shows the outstanding ability of HEMT chips on Cu substrates for solving the self-heating effect with the advantages of process simplicity,high yield,and low production requirement. 相似文献
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光诱导功能退化是胶体量子点在应用中面临的主要挑战之一,本文针对这一问题研究了使用磁控溅射沉积SiO2薄膜形成钝化层来提高CdSe/ZnS量子点发光稳定性的方法。首先,通过三正辛基膦辅助连续离子层吸附反应方法合成了615 nm发光的红色CdSe/ZnS量子点。然后将量子点旋涂在SiO2/Si基片上,再通过磁控溅射方法在量子点上沉积了厚度为20 nm的SiO2薄膜作为钝化层。使用连续波激光光源分别在空气气氛和真空条件下照射样品,研究了经过不同照射时间后钝化和未钝化量子点的稳态光致发光光谱。结果表明,随着照射时间的延长,没有SiO2钝化的量子点的PL强度显著降低、PL峰值发生蓝移、FWHM不断增大。对比研究发现,由于SiO2薄膜能够阻挡空气中的水和氧,减缓了量子点表面的光诱导氧化现象,因此显著提高了CdSe/ZnS量子点的稳定性。 相似文献
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