通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金...通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金刚石的表面形貌在氢终端处理后显著不同,光学性质则彼此相似.VGS=–4 V时,(111)金刚石器件获得的最大饱和电流为80.41 m A/mm,约为(110)金刚石器件的1.4倍;其导通电阻为48.51 W·mm,只有(110)金刚石器件导通电阻的67%.通过对器件电容-电压特性曲线的分析得到,(111)金刚石器件沟道中最大载流子密度与(110)金刚石器件差异不大.分析认为,(111)金刚石器件获得更高饱和电流和更低导通电阻,应归因于较低的方阻.展开更多
Superparamagnetic poly(acrylamide) magnetic nanogels produced via photochemical method have been developed. After Hoffmann degradation of carbonyl, the nanogels with amino groups, or poly(acrylamide-vinyl amine) magne...Superparamagnetic poly(acrylamide) magnetic nanogels produced via photochemical method have been developed. After Hoffmann degradation of carbonyl, the nanogels with amino groups, or poly(acrylamide-vinyl amine) magnetic nanogels, were also obtained. And the magnetic nanogels were further modified by methoxy poly(ethylene glycol) (MPEG) for higher dispersibility and stability. The MPEG-modified magnetic nanogels were characterized by X-ray diffraction (XRD), photo correlation spectroscopy (PCS) and scanning electron microscopy (SEM), respectively. The MPEG-modified magnetic nanogels were labeled by 188Re radiopharmaceuticals and intra-venously injected into tails of mice in the presence and absence of a 0.5 T external magnetic field targeted on the bel-lies. The radioactivity distribution was monitored in vivo. In the absence of magnetic field, the radioactivity was mainly distributed in liver, spleen, kidney, stomach and lung. In the presence of the magnetic field, the radioactivity was mainly accumulated on the targeted point, verifying the magnetically targeted character.展开更多
The conventional AlGaN/GaN high electron mobility transistor(HEMT),the AlGaN/GaN/AlGaN HEMT,and the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N HEMT are fabricated on sapphire substrates to study the drain-induced barrier-lowerin...The conventional AlGaN/GaN high electron mobility transistor(HEMT),the AlGaN/GaN/AlGaN HEMT,and the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N HEMT are fabricated on sapphire substrates to study the drain-induced barrier-lowering(DIBL)effect.It is found that the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N HEMT with AlGaN channel has the lowest DIBL coefficient of 6.7 mV/V compared with the other two HEMTs.This is attributed to the best two-dimensional electron gas confinement of the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N structure.This opinion is further confirmed by the conduction band diagrams and electron distribution calculated from the one-dimensional Poisson–Schrödinger equation.展开更多
文摘通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金刚石的表面形貌在氢终端处理后显著不同,光学性质则彼此相似.VGS=–4 V时,(111)金刚石器件获得的最大饱和电流为80.41 m A/mm,约为(110)金刚石器件的1.4倍;其导通电阻为48.51 W·mm,只有(110)金刚石器件导通电阻的67%.通过对器件电容-电压特性曲线的分析得到,(111)金刚石器件沟道中最大载流子密度与(110)金刚石器件差异不大.分析认为,(111)金刚石器件获得更高饱和电流和更低导通电阻,应归因于较低的方阻.
基金Supported by Science and Technology Commission of Shanghai Municipality (No.0352nm120) and the Knowledge Innovation Pro-ject of Chinese Academy of Sciences (No.90120310).
文摘Superparamagnetic poly(acrylamide) magnetic nanogels produced via photochemical method have been developed. After Hoffmann degradation of carbonyl, the nanogels with amino groups, or poly(acrylamide-vinyl amine) magnetic nanogels, were also obtained. And the magnetic nanogels were further modified by methoxy poly(ethylene glycol) (MPEG) for higher dispersibility and stability. The MPEG-modified magnetic nanogels were characterized by X-ray diffraction (XRD), photo correlation spectroscopy (PCS) and scanning electron microscopy (SEM), respectively. The MPEG-modified magnetic nanogels were labeled by 188Re radiopharmaceuticals and intra-venously injected into tails of mice in the presence and absence of a 0.5 T external magnetic field targeted on the bel-lies. The radioactivity distribution was monitored in vivo. In the absence of magnetic field, the radioactivity was mainly distributed in liver, spleen, kidney, stomach and lung. In the presence of the magnetic field, the radioactivity was mainly accumulated on the targeted point, verifying the magnetically targeted character.
基金Supported by the National S&T Project of China under Grant Nos 2011ZX01002-002 and 2013ZX02308-002the National Natural Science Foundation of China under Grant Nos 61204006 and 61106063.
文摘The conventional AlGaN/GaN high electron mobility transistor(HEMT),the AlGaN/GaN/AlGaN HEMT,and the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N HEMT are fabricated on sapphire substrates to study the drain-induced barrier-lowering(DIBL)effect.It is found that the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N HEMT with AlGaN channel has the lowest DIBL coefficient of 6.7 mV/V compared with the other two HEMTs.This is attributed to the best two-dimensional electron gas confinement of the Al_(x)Ga_(1-x)N/Al_(y)Ga_(1-y)N structure.This opinion is further confirmed by the conduction band diagrams and electron distribution calculated from the one-dimensional Poisson–Schrödinger equation.
