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通过激光辐照固态Al膜,制备了一种p型重掺杂4H-SiC,分析了Al膜厚度、激光脉冲个数对掺杂结果的影响,验证了不同工艺参数对p型掺杂层表面电学性能的调控作用。结果表明,当Al膜厚度为120nm,脉冲个数为50时,掺杂试样的最大载流子浓度为6.613×10~(17) cm~(-3),最小体电阻率为17.36Ω·cm,掺杂浓度(粒子数浓度)可达6.6×10~(19) cm~(-3)。4H-SiC的Al掺杂改性机理为:在紫外激光作用下,Si—C键断裂,Al原子替代Si原子形成p型掺杂层。 相似文献
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UCLA,JPL和Epitronics报道了在半绝缘4H-SiC衬底上生长的非掺杂沟道Al0.30Ga0.70N/GaN HFET,器件没有制作空气桥,获得的fmax达到了107GHz的新记录.该器件包括一个100nm AlN缓冲层、1.25nm的未掺杂GaN、3nm的未掺Al0.30Ga0.70N和n型重掺杂(Si=1×1019cm-3)的30nm的Al0.30Ga0.70N层.栅长为0.2μm,由于在AlGaN层中的Al含量高和n型掺杂重,获得的源漏欧姆接触电阻为0.15Ω*mm.除了优越的频率特性,该器件的跨导为260mS/mm(栅的反向偏置电压为3.5V),饱和电流密度为1.2A/mm. 相似文献
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采用旋涂法和自组装成膜法制备了不同厚度的Rh-6G/DNA-CTMA复合薄膜.通过对Rh-6G/DNA-CTMA薄膜的表面形貌、Rh-6G/DNA-CTMA样品溶液及薄膜的紫外/可见吸收光谱和透过率的测量,以及对薄膜样品交流电阻的表征,研究了薄膜的光电特性与成膜质量.实验结果表明:制备的Rh-6G/DNA-CTMA溶液在533 nm处出现吸收峰,且随着掺杂Rh-6G浓度的增加吸收增强,在其他波段无明显吸收;制备的Rh-6G/DNA-CTMA掺杂薄膜在小于280 nm范围只有很小的透射,在540 nm处有明显吸收.此外,未掺杂薄膜的交流电阻随着频率的增加而减小,而掺杂薄膜的交流电阻的变化相反,并在频率为10 MHz和55 MHz处出现明显的突变. 相似文献
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以CzHQZn为主体的有机发光器件的发光效率 总被引:1,自引:0,他引:1
采用真空热蒸镀技术,分别制备了结构为ITO/2T-NATA(25nm)/CzHQZn(10~25nm)/TPBi(35nm)/LiF(0.5nm)/Al、ITO/2T-NATA(30nm)/CBP:6%Ir(ppy)3:x%CzHQZn(20nm)/Alq3(50nm)/LiF(0.5nm)/Al和ITO/2T-NATA(30nm)/CBP:6%Ir(ppy)3:10%CzHQZn(xnm)/Alq3((70-x)nm)/LiF(0.5nm)/Al的3组有机电致发光器件(OLED)。器件中,CzHQZn既有空穴传输特性,又是黄光发射的主体。为了提高其发光效率,利用磷光敏化技术,研究了掺杂层中不同掺杂浓度和掺杂层不同厚度时器件的发光效率。结果表明,器件的效率随着掺杂发光层的厚度和掺杂浓度的变化而改变,当发光层的厚度为18nm时,CzHQZn掺杂浓度为10%的器件性能较好;在10V电压下,器件的最大电流效率达到3.26cd/A,色坐标为(0.4238,0.5064),最大亮度达到17560cd/m2。 相似文献
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本文研究了稀土掺杂硒化钼(MoSe2)垂直纳米线 的制备及光学特性。以分析纯硒化钼 粉末为原料,采用热蒸发方法在Si衬底上沉积硒化钼垂直纳米线,并在其生长过程中利用硝 酸鉺进行原位掺杂。利用原子力显微镜(AFM)、X射线衍射仪(XRD)、紫外-可见分光光度计 和 荧光光谱仪研究了掺杂硒化钼薄膜的表面形貌﹑晶体结构﹑光吸收和特性。发现掺杂后MoSe 2纳米线的结晶性更强,长度增加2倍以上。同时,掺杂后纳米线的可见光吸收和光致发光 强 度明显增强,760 nm处MoSe2纳米线的带间跃迁的本征发射增强4倍 以上。另外,Er3+掺杂后 ,在590 nm和650 nm处增加了2个来自Er3+离子的发射,说明稀土掺杂后发光峰增加,使 光谱谱线更加丰富。以上结果表明,稀土掺杂可显著增强硒化钼的结晶性、光吸收和发光效 率,使其可用于制备超薄、高效率的太阳能电池、光探测器等光电子器件。 相似文献
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Al,Al/C and Al/Si implantations in 6H-SiC 总被引:1,自引:0,他引:1
Mulpuri V. Rao Peter Griffiths Jason Gardner O. W. Holland M. Ghezzo J. Kretchmer G. Kelner J. A. Freitas 《Journal of Electronic Materials》1996,25(1):75-80
Multiple-energy Al implantations were performed with and without C or Si coimplantations into 6H-SiC epitaxial layers and
bulk substrates at 850°C. The C and Si co-implantations were used as an attempt to improve Al acceptor activation in SiC.
The implanted material was annealed at 1500, 1600, and 1650°C for 45 min. The Al implants are thermally stable at all annealing
temperatures and Rutherford backscattering via channeling spectra indicated good lattice quality in the annealed Al-implanted
material. A net hole concentration of 8 × 1018 cm−3 was measured at room temperature in the layers implanted with Al and annealed at 1600°C. The C or Si co-implantations did
not yield improvement in Al acceptor activation. The co-implants resulted in a relatively poor crystal quality due to more
lattice damage compared to Al implantation alone. The out-diffusion of Al at the surface is more for 5Si co-implantation compared
to Al implant alone, where 5Si means a Si/Al dose ratio of 5. 相似文献
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J. H. Edgar Z. J. Yu David J. Smith J. Chaudhuri X. Cheng 《Journal of Electronic Materials》1997,26(12):1389-1393
The structure and crystal quality of epitaxial films of SiC/AlN/6H-SiC(0001) prepared by chemical vapor deposition were evaluated
by high resolution transmission electron microscopy (HRTEM) and x-ray diffraction techniques. Cross-sectional HRTEM revealed
an abrupt AlN layer-6H-SiC substrate junction, but the transition between the AlN and SiC layers was much rougher, leading
to the formation of a highly disordered SiC region adjacent to the interface. The AlN layer was relatively defect free, while
the SiC layer contained many microtwins and stacking faults originating at the top SiC/AlN interface. The SiC layer was the
3C-polytype, as determined by double crystal x-ray rocking curves. The SiC layers were under in-plane compressive stress,
with calculated defect density between 2–4×107 defects/cm−2. 相似文献
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Byung-Teak Lee Jong-Yoon Shin Seon-Hoon Kim Jin-Hyeok Kim Sang-Yoon Han Jong Lam Lee 《Journal of Electronic Materials》2003,32(6):501-504
Interfacial reactions, surface morphology, and current-voltage (I-V) characteristics of Ti/Al/4H-SiC and TiN/Al/4H-SiC were
studied before and after high-temperature annealing. It was observed that surface smoothness of the samples was not significantly
affected by the heat treatment at up to 900°C, in contrast to the case of Al/SiC. Transmission electron microscopy (TEM) observation
of the Ti(TiN)/Al/SiC interface showed that Al layer reacted with the SiC substrate at 900°C and formed an Al-Si-(Ti)-C compound
at the metal/SiC interface, which is similar to the case of the Al/SiC interface. The I-V measurement showed reasonable ohmic
properties for the Ti/Al films, indicating that the films can be used to stabilize the Al/SiC contact by protecting the Al
layer from the potential oxidation and evaporation problem, while maintaining proper contact properties. 相似文献
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为了获得高质量4H-SiC外延材料,研制出一套水平式低压热壁CVD(LP-HWCVD)生长系统,在偏晶向的4H-SiC Si(0001)晶面衬底上,利用"台阶控制生长"技术进行了4H-SiC的同质外延生长,典型生长温度和压力分别为1500℃和1.3×103Pa,生长速率控制在1.0μm/h左右.采用Nomarski光学显微镜、扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射、Raman散射以及低温光致发光测试技术,研究了4H-SiC的表面形貌、结构和光学特性以及用NH3作为n型掺杂剂的4H-SiC原位掺杂技术,并在此基础上获得了4H-SiC p-n结二极管以及它们在室温及400℃下的电致发光特性,实验结果表明4H-SiC在Si不能工作的高温环境下具有极大的应用潜力. 相似文献
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研究了钒掺杂生长半绝缘6H-SiC的补偿机理.二次离子质谱分析结果表明,非故意掺杂生长的6H-SiC中,氮是主要的剩余浅施主杂质.通过较深的钒受主能级对氮施主的补偿作用,得到了具有半绝缘特性的SiC材料.借助电子顺磁共振和吸收光谱分析,发现SiC中同时存在中性钒(V4+)和受主态钒(V3+)的电荷态,表明掺入的部分杂质钒通过补偿浅施主杂质氮,形成受主态钒,这与二次离子质谱分析结果相吻合.通过对样品进行吸收光谱和低温光致发光测量,发现钒受主能级在6H-SiC中位于导带下0.62eV处. 相似文献
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研究了钒掺杂生长半绝缘6H-SiC的补偿机理.二次离子质谱分析结果表明,非故意掺杂生长的6H-SiC中,氮是主要的剩余浅施主杂质.通过较深的钒受主能级对氮施主的补偿作用,得到了具有半绝缘特性的SiC材料.借助电子顺磁共振和吸收光谱分析,发现SiC中同时存在中性钒(V4 )和受主态钒(V3 )的电荷态,表明掺入的部分杂质钒通过补偿浅施主杂质氮,形成受主态钒,这与二次离子质谱分析结果相吻合.通过对样品进行吸收光谱和低温光致发光测量,发现钒受主能级在6H-SiC中位于导带下0.62eV处. 相似文献
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