A 4.69-W/mm output power density InAlN/GaN HEMT grown on sapphire substrate

We report high performance InA1N/GaN HEMTs grown on sapphire substrates. The lattice-matched InA1N/GaN HEMT sample showed a high 2DEG mobility of 1210 cmZ/（V.s） under a sheet density of 2.6 × 10^13 cm^-2. Large signal load-pull measurements for a （2 × 100 μm） x 0.25 μm device have been conducted with a drain voltage of 24 V at 10 GHz. The presented results confirm the high performances reachable by InAIN- based technology with an output power density of 4.69 W/ram, a linear gain of 11.8 dB and a peak power-added efficiency of 48%. This is the first report of high performance InA1N/GaN HEMTs in China's Mainland.

Development of Surface Grating Distributed Feedback Quantum Cascade Laser for High Output Power and Low Threshold Current Density

We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.

Influence of fin architectures on linearity characteristics of AlGaN/GaNFinFETs

We investigate the influence of fin architecture on linearity characteristics of AlGaN/GaNFinFET.It is found that the Fin FET with scaled fin dimensions exhibits much flatter Gm characteristics than the one with long fins as well as planar HEMT.According to the comparative study,we provide direct proof that source resistance rather than tri-gate structure itself dominates the Gm behavior.Furthermore,power measurements show that the optimized FinFET is capable of delivering a much higher output power density along with significant improvement in linearity characteristics than conventional planar HEMT.This study also highlights the importance of fin design in GaN-based FinFET for microwave power application,especially high-linearity applications.

通过二维层状结构搭建能量和声子势垒提高InSb热电性能

InSb是一种具有闪锌矿结构的窄带隙半导体,在光电探测器、红外热成像、霍尔器件等领域有着广泛的应用.良好的能带结构、超高的电子迁移率和无毒性质表明InSb可能是一种潜在的中温热电材料.InSb当前面临着一些关键挑战,如高导热系数和小Seebeck系数,导致其超高的晶格导热系数,进而低的ZT值.鉴于此,我们发展了一种z wt%QSe_(2)(Q=Sn,W)纳米复合的高效策略,即通过对二维层状QSe_(2)的纳米复合,在InSb体系中引入Q_(In)^(+)和Se_(Sb)^(+)点缺陷.此外,本征WSe_(2)的价带作为势垒可以散射相当数量的空穴载流子,导致本征激发阶段的Seebeck系数升高.此外,无序分布的纳米片/粒子和位错可以有效地阻碍热流扩散,形成热声子的强散射.结果表明,3%WSe_(2)样品的功率因子提高到~33.3μW cm^(-1)K^(-2),733 K时ZT值提高到~0.82,工程输出功率密度ω_(max)~233μW cm^(-1),工程热电转换效率η~5.2%.