采用光荧光和阴极荧光方法 ,对 Ga N外延层中的黄色和蓝色发光进行测量分析 ;同时 ,采用原子力显微镜、扫描电镜及其能谱测量外延层中的缺陷。结果表明 ,黄色和蓝色发光与残留杂质有关。采用第一原理计算结果显示 ,残留 C、O杂质、本征...采用光荧光和阴极荧光方法 ,对 Ga N外延层中的黄色和蓝色发光进行测量分析 ;同时 ,采用原子力显微镜、扫描电镜及其能谱测量外延层中的缺陷。结果表明 ,黄色和蓝色发光与残留杂质有关。采用第一原理计算结果显示 ,残留 C、O杂质、本征缺陷等是黄色和蓝色的可能物理起源。采用原子力显微镜、扫描电镜、透射电镜及其能谱对 Ga N/Al Ga N异质结中的纳米管进行观测 ,了解了纳米管的形貌。结果表明 ,构成纳米管的小面可能是外延过程中表面吸附引起的 ;计算结果显示 ,纳米管形貌变化与 Ga N/Al Ga N界面处晶格失配应力有关。采用透射电镜观察外延层中沉积物及其周围位错的结构表明 。展开更多
利用Al Ga N/Ga N半导体的极化效应在异质结界面产生二维电子气(2DEG)的特性,设计了一种基于高电子迁移率场效应管(HEMT)的压强传感器;并利用标准的微电子工艺和背部深硅刻蚀技术制作了器件;对器件在不同压强下的源-漏I-V特性进行了测...利用Al Ga N/Ga N半导体的极化效应在异质结界面产生二维电子气(2DEG)的特性,设计了一种基于高电子迁移率场效应管(HEMT)的压强传感器;并利用标准的微电子工艺和背部深硅刻蚀技术制作了器件;对器件在不同压强下的源-漏I-V特性进行了测试和评价.结果表明本文设计制作的压强传感器的I-V特性对压强的变化能做出灵敏的反应.Ⅲ族氮化物半导体器件具有高速度、高灵敏、大功率和耐高温等特点,本压强传感器具有更广的应用领域.展开更多
The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-...The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEDs with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.展开更多
We have developed a superior solar-blind ultraviolet （UV） photocathode with an AlxGa1_xrN photocathode （x ～ 0.45） in semi-transparent mode, and assessed spectra radiant sensitivity related to practical use. Betbr...We have developed a superior solar-blind ultraviolet （UV） photocathode with an AlxGa1_xrN photocathode （x ～ 0.45） in semi-transparent mode, and assessed spectra radiant sensitivity related to practical use. Betbre being grown over a basal plane sapphire substrate by low-pressure metal organic chemical vapor deposition （MOCVD）, a reasonable design was made to the photocathode epitaxy structure, focusing on the AlxGa1_xN： Mg active layer, then followed by a comprehen- sive analysis of the structural and optical characterization. The spectra radiant sensitivity is peaked of 41.395 mA/W at wavelength 257 nm and then decreases by about 3 to 4 decades at 400 nm demonstrating the ability of this photocathode for solar-blind application prospects.展开更多
N-polar and Ⅲ-polar GaN and AlN epitaxial thin films grown side by side on single sapphire substrate was reported.Surface morphology,wet etching susceptibility and bi-axial strain conditions were investigated and the...N-polar and Ⅲ-polar GaN and AlN epitaxial thin films grown side by side on single sapphire substrate was reported.Surface morphology,wet etching susceptibility and bi-axial strain conditions were investigated and the polarity control scheme was utilized in the fabrication of Schottky barrier diode where ohmic contact and Schottky contact were deposited on N-polar domains and Ga-polar domains,respectively.The influence of N-polarity on on-state resistivity and Ⅰ–Ⅴ characteristic was discussed,demonstrating that lateral polarity structure of GaN and AlN can be widely used in new designs of optoelectronic and electronic devices.展开更多
Using the measured capacitance-voltage curves ofNi/Au Schottky contacts with different areas and the current-voltage characteristics for the A1GaAs/GaAs, A1GaN/A1N/GaN and InoAsA10.szN/A1N/GaN heterostructure field-ef...Using the measured capacitance-voltage curves ofNi/Au Schottky contacts with different areas and the current-voltage characteristics for the A1GaAs/GaAs, A1GaN/A1N/GaN and InoAsA10.szN/A1N/GaN heterostructure field-effect transistors （HFETs） at low drain-source voltage, the two-dimensional electron gas （2DEG） electron mobility for the prepared HFETs was calculated and analyzed. It was found that there is an obvious difference for the variation trend of the mobility curves between the Ⅲ-V nitride HFETs and the A1GaAs/GaAs HFETs. In the III-V nitride HFETs, the variation trend for the curves of the 2DEG electron mobility with the gate bias is closely related to the ratio of the gate length to the drainto-source distance. While the ratio of the gate length to the drainto-source distance has no effect on the variation trend for the curves of the 2DEG electron mobility with the gate bias in the A1GaAs/GaAs HFETs. The reason is attributed to the polarization Coulomb field scattering in the Ⅲ-V nitride HFETs.展开更多
文摘采用光荧光和阴极荧光方法 ,对 Ga N外延层中的黄色和蓝色发光进行测量分析 ;同时 ,采用原子力显微镜、扫描电镜及其能谱测量外延层中的缺陷。结果表明 ,黄色和蓝色发光与残留杂质有关。采用第一原理计算结果显示 ,残留 C、O杂质、本征缺陷等是黄色和蓝色的可能物理起源。采用原子力显微镜、扫描电镜、透射电镜及其能谱对 Ga N/Al Ga N异质结中的纳米管进行观测 ,了解了纳米管的形貌。结果表明 ,构成纳米管的小面可能是外延过程中表面吸附引起的 ;计算结果显示 ,纳米管形貌变化与 Ga N/Al Ga N界面处晶格失配应力有关。采用透射电镜观察外延层中沉积物及其周围位错的结构表明 。
文摘利用Al Ga N/Ga N半导体的极化效应在异质结界面产生二维电子气(2DEG)的特性,设计了一种基于高电子迁移率场效应管(HEMT)的压强传感器;并利用标准的微电子工艺和背部深硅刻蚀技术制作了器件;对器件在不同压强下的源-漏I-V特性进行了测试和评价.结果表明本文设计制作的压强传感器的I-V特性对压强的变化能做出灵敏的反应.Ⅲ族氮化物半导体器件具有高速度、高灵敏、大功率和耐高温等特点,本压强传感器具有更广的应用领域.
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/M01326X/1)
文摘The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEDs with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.
基金supported by the National Natural Science Foundation of China(Grant No.10974015)the National Defense Pre-Research Foundation of China(Grant No.9140C380502150C38002)
文摘We have developed a superior solar-blind ultraviolet （UV） photocathode with an AlxGa1_xrN photocathode （x ～ 0.45） in semi-transparent mode, and assessed spectra radiant sensitivity related to practical use. Betbre being grown over a basal plane sapphire substrate by low-pressure metal organic chemical vapor deposition （MOCVD）, a reasonable design was made to the photocathode epitaxy structure, focusing on the AlxGa1_xN： Mg active layer, then followed by a comprehen- sive analysis of the structural and optical characterization. The spectra radiant sensitivity is peaked of 41.395 mA/W at wavelength 257 nm and then decreases by about 3 to 4 decades at 400 nm demonstrating the ability of this photocathode for solar-blind application prospects.
基金Project partially supported by the National Key Research and Development Program of China(No.2016YFB0400802)the National Natural Science Foundation of China(No.61704176)the Open project of Zhejiang Key Laboratory for Advanced Microelectronic Intelligent Systems and Applications(No.ZJUAMIS1704)
文摘N-polar and Ⅲ-polar GaN and AlN epitaxial thin films grown side by side on single sapphire substrate was reported.Surface morphology,wet etching susceptibility and bi-axial strain conditions were investigated and the polarity control scheme was utilized in the fabrication of Schottky barrier diode where ohmic contact and Schottky contact were deposited on N-polar domains and Ga-polar domains,respectively.The influence of N-polarity on on-state resistivity and Ⅰ–Ⅴ characteristic was discussed,demonstrating that lateral polarity structure of GaN and AlN can be widely used in new designs of optoelectronic and electronic devices.
文摘围绕Ⅲ族氮化物半导体在紫外战术导弹逼近告警系统中的潜在应用前景,设计出一种基于新型Ⅲ族氮化物半导体光电阴极的紫外变像管,确定了影响光电阴极光电发射性能的Al摩尔组分、膜层厚度和P型掺杂水平。利用高分辨率X射线衍射仪和紫外分光光度计,对光电阴极结构和光学日盲特性进行仿真分析和测试。紫外变像管的光谱辐射灵敏度测试结果显示:探测器像管的辐射灵敏度在220~270 nm波段范围内波动较小,在波长266 nm处的辐射灵敏度为39.7 m A/W,光谱响应从波长270 nm之后开始急剧下降,表明其本征具有良好的日盲紫外属性。基于变像管的光谱辐射灵敏度测试结果及信噪比的作用距离模型,采用MODTRAN大气模拟软件包对以此变像管为核心探测器件的导弹逼近告警系统作用距离进行迭代求解。计算结果显示:导弹逼近告警系统的作用距离可达到7.1 km.
基金Project supported by the National Natural Science Foundation of China(No.11174182)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20110131110005)the Graduate Independent Innovation Foundation of Shandong University,GIIFSDU(No.yzc12064)
文摘Using the measured capacitance-voltage curves ofNi/Au Schottky contacts with different areas and the current-voltage characteristics for the A1GaAs/GaAs, A1GaN/A1N/GaN and InoAsA10.szN/A1N/GaN heterostructure field-effect transistors （HFETs） at low drain-source voltage, the two-dimensional electron gas （2DEG） electron mobility for the prepared HFETs was calculated and analyzed. It was found that there is an obvious difference for the variation trend of the mobility curves between the Ⅲ-V nitride HFETs and the A1GaAs/GaAs HFETs. In the III-V nitride HFETs, the variation trend for the curves of the 2DEG electron mobility with the gate bias is closely related to the ratio of the gate length to the drainto-source distance. While the ratio of the gate length to the drainto-source distance has no effect on the variation trend for the curves of the 2DEG electron mobility with the gate bias in the A1GaAs/GaAs HFETs. The reason is attributed to the polarization Coulomb field scattering in the Ⅲ-V nitride HFETs.
