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Photonic band structure of one-dimensional metal/dielectric structures calculated by the plane-wave expansion method

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Science China(Physics,Mechanics & Astronomy) 2015年第7期58卷 84-89页

作者： ZONG YiXin XIA JianBai The state Key laboratory of superlattices and microstructures Institute of Semiconductors Chinese Academy of Sciences

The plane-wave expansion(PWE) method is employed to calculate the photonic band structures of metal/dielectric(M/D) periodic systems. We consider a one-dimensional(1D) M/D superlattice with a metal layer characterized by a frequency-dependent dielectric function. To calculate the photonic band of such a system, we propose a new method and thus avoid solving the nonlinear eigenvalue equations. We obtained the frequency dispersions and the energy distributions of eigen-modes of 1D superlattices. This general method is applicable to calculate the photonic band of a broad class of physical systems, e.g. 2D and 3D M/D photonic crystals. For comparison, we present a simple introduction of the finite-difference(FD) method to calculate the same system, and the agreement turns out to be good. But the FD method cannot be applied to the TM modes of the M/D superlattice.

关键词： photonic crystal PWE method frequency dispersion energy distribution

Recent progress in perpendicularly magnetized Mn-based binary alloy films

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Chinese Physics B 2013年第11期22卷 33-45页

作者：朱礼军聂帅华赵建华 state Key laboratory of superlattices and microstructures Institute of Semiconductors Chinese Academy of Sciences

In this article, we review the recent progress in growth, structural characterizations, magnetic properties, and related spintronic devices of tetragonal MnxGa and MnxA1 thin films with perpendicular magnetic anisotropy. First, we present a brief introduction to the demands for perpendicularly magnetized materials in spintronics, magnetic recording, and perma- nent magnets applications, and the most promising candidates of tetragonal MnxGa and MnxA1 with strong perpendicular magnetic anisotropy. Then, we focus on the recent progress of perpendicularly magnetized MnxGa and MnxA1 respec- tively, including their lattice structures, bulk synthesis, epitaxial growth, structural characterizations, magnetic and other spin-dependent properties, and spintronic devices like magnetic tunneling junctions, spin valves, and spin injectors into semiconductors. Finally, we give a summary and a perspective of these perpendicularly magnetized Mn-based binary alloy films for future applications.

关键词： spintronics magnetic material perpendicular magnetic anisotropy spin polarized transport insemiconductors

A 256×256 time-of-flight image sensor based on center-tap demodulation pixel structure

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Science China(Information Sciences) 2016年第4期59卷 132-141页

作者： Zhe CHEN Shan DI Zhongxiang CAO Qi QIN Fei JI Liyuan LIU Nanjian WU state Key laboratory for superlattices and microstructures Institute of SemiconductorsChinese Academy of Sciences

This paper proposes a 256×256 time-of-flight(TOF) image sensor based on the center-tap(CT)demodulation pixel structure. The image sensor can capture both the two-dimensional(2D) high speed image and the three-dimensional(3D) depth image. The CT pixel consists of two split pinned photodiode(PPD)regions and two pairs of transfer transistors. The transfer transistors adopt a non-uniform doped channel(NUDC) structure, which can increase the electron transfer speed along the transfer channel and eliminate the image lag for high speed imaging. The pixel size is 10 μm×10 μm, and we design the implementation process of the pixel to increase the electron transfer speed. The sensor is fabricated in a 0.18 μm 1P5 M CMOS image sensor process. Test results show that it can capture the 430-fps intensity image and the 90-fps depth image in two different imaging modes. The rectified non-linearity within the 1.0–7.5 m depth measurement range achieves less than 3 cm, and the measurement accuracy achieves 4.0 cm at 2.5 m, corresponding to the relative error of1.6%.

关键词： CMOS image sensor demodulation pixel depth image pinned photodiode time-of-flight(TOF)

A low power global shutter pixel with extended FD voltage swing range for large format high speed CMOS image sensor

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Science China(Information Sciences) 2015年第4期58卷 166-175页

作者： ZHOU YangFan CAO ZhongXiang HAN Ye LI QuanLiang SHI Cong DOU RunJiang QIN Qi LIU Jian WU NanJian state Key laboratory for superlattices and microstructures Institute of SemiconductorsChinese Academy of Sciences

A low power 8T global shutter pixel with extended FD voltage swing range is proposed for large format high speed CMOS image sensor. The pixel has a negative threshold reset transistor, two in-pixel source followers, and a sample-and-hold circuit. The in-pixel first source follower is employed for reducing the pixel average current and maximum transient current. The negative threshold reset transistor is applied to extend the voltage swing of FD. Using pixel level sample-and-hold circuit, the k TC noise on FD node can be effectively nullified by correlated double sampling operation. A high speed 1000 fps 256×256 CMOS image sensor is implemented in 0.18 μm CMOS process. Two 10-bit cyclic ADC arrays are integrated in this prototype sensor chip. The active area of the chip is 10 mm×7 mm with a pixel size of 14 μm×14 μm. The developed sensor achieves an average current of 23 n A per pixel, a maximum transit current per pixel as low as 1113 n A, and a large FD voltage swing of 1.78 V. The sensor temporal noise level is 103 e-and full well capacity has 27000 e-which results in 48.3 d B signal dynamic range.

关键词： global shutter CDS low power negative threshold reset transistor high speed image sensor

Molecular beam epitaxy growth of GaAs on an offcut Ge substrate

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Chinese Physics B 2011年第1期20卷 647-652页

作者：贺继方牛智川常秀英倪海桥朱岩李密锋尚向军 state Key laboratory for superlattices and microstructures Institute of SemiconductorsChinese Academy of Sciences

Molecular beam epitaxy growth of GaAs on an offcut Ge （100） substrate has been systemically investigated. A high quality GaAs/Ge interface and CaAs film on Ge have been achieved. High temperature annealing before GaAs deposition is found to be indispensable to avoid anti-phase domains. The quality of the GaAs film is found to strongly depend on the GaAs/Ge interface and the beginning of GaAs deposition. The reason why both high temperature annealing and GaAs growth temperature can affect epitaxial GaAs film quality is discussed. High quality InonTGao.s3As/GaAs strained quantum wells have also been achieved on a Ge substrate. Samples show flat surface morphology and narrow photoluminescence line width compared with the same structure sample grown on a GaAs substrate. These results indicate a large application potential for Ⅲ-Ⅴcompound semiconductor optoelectronic devices on Ge substrates.

关键词： molecular beam epitaxy anti-phase domain GaAs/Ge interface

A passive UHF RFID tag chip with a dual-resolution temperature sensor in a 0.18μm standard CMOS process

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Journal of Semiconductors 2011年第11期32卷 139-147页

作者：冯鹏章琦吴南健 state Key laboratory for superlattices and microstructures Institute of SemiconductorsChinese Academy of Sciences

This paper presents a passive EPC Gen-2 UHF RFID tag chip with a dual-resolution temperature sensor. The chip tag integrates a temperature sensor, an RF/analog front-end circuit, an NVM memory and a digital base- band in a standard CMOS process. The sensor with a low power sigma-delta （NA） ADC is designed to operate in low and high resolution modes. It can not only achieve the target accuracy but also reduce the power consumption and the sensing time. A CMOS-only RF rectifier and a single-poly non-volatile memory （NVM） are designed to realize a low cost tag chip. The 192-bit-NVM tag chip with an area of 1 mm2 is implemented in a 0.18-#m standard CMOS process. The sensitivity of the tag is -10.7 dBm/-8.4 dBm when the sensor is disabled/enabled. It achieves a maximum reading/sensing distance of 4 m/3.1 m at 2 W EIRR The inaccuracy of the sensor is -0.6 ℃/0.5 ℃ （-1.0 ℃/1.2 ℃） in the operating range from 5 to 15 ℃ in high resolution mode （-30 to 50 ℃ in low resolution mode）. The resolution of the sensor achieves 0.02 ℃ （0.18 ℃） in high （low） resolution mode.

关键词： RFID temperature sensor passive UHF tag

A novel noise optimization technique for inductively degenerated CMOS LNA

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Journal of Semiconductors 2009年第10期30卷 137-142页

作者：耿志卿王海永吴南健 state Key laboratory for superlattices and microstructures Institute of Semiconductors Chinese Academy of Sciences

This paper proposes a novel noise optimization *** technique gives analytical formulae for the noise performance of inductively degenerated CMOS low noise amplifier（LNA）circuits with an ideal gate inductor for a fixed bias voltage and nonideal gate inductor for a fixed power dissipation,respectively,by mathematical analysis and reasonable approximation *** circuits with required noise figure can be designed effectively and rapidly just by using hand calculations of the proposed *** design a 1.8 GHz LNA in a TSMC 0.25 μm CMOS *** measured results show a noise figure of 1.6 dB with a forward gain of 14.4 dB at a power consumption of 5 mW,demonstrating that the designed LNA circuits can achieve low noise figure levels at low power dissipation.

关键词： low noise optimization noise factor

Influence of growth temperatures on the quality of InGaAs/GaAs quantum well structure grown on Ge substrate by molecular beam epitaxy

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Journal of Semiconductors 2011年第4期32卷 39-43页

作者：贺继方尚向军李密锋朱岩常秀英倪海桥徐应强牛智川 state Key laboratory for superlattices and microstructures Institute of SemiconductorsChinese Academy of Sciences

Molecular beam epitaxy growth of an In;Ga;As/GaAs quantum well（QW） structure（x equals to 0.17 or 0.3） on offcut（100） Ge substrate has been *** samples were characterized by atomic force microscopy,photoluminescence（PL）,and high resolution transmission electron *** temperature annealing of the Ge substrate is necessary to grow GaAs buffer layer without anti-phase *** the subsequent growth of the GaAs buffer layer and an In;Ga;As/GaAs QW structure,temperature plays a key role. The mechanism by which temperature influences the material quality is *** quality In;Ga;As/GaAs QW structure samples on Ge substrate with high PL intensity,narrow PL linewidth and flat surface morphology have been achieved by optimizing growth *** results show promising device applications forⅢ-Ⅴcompound semiconductor materials grown on Ge substrates.

关键词： Ge substrate InGaAs/GaAs quantum well molecular beam epitaxy

Stability of the positively charged manganese centre in GaAs heterostructures examined theoretically by the effective mass approximation calculation near the Γ critical point

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Chinese Physics B 2011年第10期20卷 15-22页

作者：王丽国申超郑厚植朱汇赵建华 state Key laboratory for superlattices and microstructures Institute of Semiconductors Chinese Academy of Sciences

This paper describes an n-i-p-i-n model heterostructure with a manganese （Mn）-doped p-type base region to check the stability of a positively charged manganese A＋Mn centre with two holes weakly bound by a negatively charged 3dS（Mn） core of a local spin S = 5/2 in the framework of the effective mass approximation near the F critical point （k -0）. By including the carrier screening effect, the ground state energy and the binding energy of the second hole in the positively charged centre A＋Mn are calculated within a hole concentration range from 1 ×10^16 cm-3 to 1 × 10^17 cm^-3, which is achievable by biasing the structure under photo-excitation. For comparison, the ground-state energy of a single hole in the neutral AMn centre is calculated in the same concentration range. It turns out that the binding energy of the second hole in the A＋Mn centre varies from 9.27 meV to 4.57 meV. We propose that the presence of the A＋Mn centre can be examined by measuring the photoluminescence from recombination of electrons in the conduction band with the bound holes in the A＋Mn centre since a high frequency dielectric constant of ε∞ = 10.66 can be safely adopted in this case. The novel feature of the ability to tune the impurity level of the A＋Mn centre makes it attractive for optically and electrically manipulating local magnetic spins in semiconductors.

关键词： charged acceptor centre screening effect exchange interaction