非对称In0.53Ga0.47As/In0.52Al0.48As量子阱的零场自旋分裂能与高场g因子

我们研究了非对称In_0.53Ga_0.47As/In_0.52Al_0.48As量子阱中二维电子气的磁输运性质,所测量的样品的径向磁阻Rxx的Shubinikov-de Haas振荡没有呈现出拍频的特征。通过测量样品的弱局域效应提取了其零场自旋分裂能并通过对自旋分裂的Rxx双峰间距随倾斜角度theta的依赖关系的拟合提取了高场下的有效g因子。样品的Dingle plot图呈现非线性和特征,这可以归因于来自样品衬底附近的掺杂Be原子的长程势散射效应。     

截止频率为218GHz的超高速晶格匹配In0.53Ga0.47As/In0.52Al0.48As高电子迁移率晶体管

报道了截止频率为218GHz的晶格匹配的In0.53Ga0.47As/In0.52Al0.48As高电子迁移率晶体管,这是迄今为止国内报道的截止频率最高的高电子迁移率晶体管,器件直流特性也很优异：跨导为980mS/mm,最大电流密度为870mA/mm,文中的材料结构和所有器件制备工艺均为本研究小组自主研制开发。     

功率增益截止频率为183GHz的In0.53Ga0.47As/In0.52Al0.48As HEMTs

通过合理的外延层材料结构设计和改进的器件制备工艺,制备出功率增益截止频率(fmax)为183GHz的晶格匹配InP基In0.53Ga0.47As-In0.52Al0.48As HEMT.该fmax为国内HEMT器件最高值.还报道了器件的结构、制备工艺以及器件的直流和高频特性.     

截止频率为218GHz的超高速晶格匹配In0.53Ga0.47As/In0.52Al0.48As高电子迁移率晶体管

报道了截止频率为218GHz的晶格匹配的In0.53Ga0.47As/In0.52Al0.48As高电子迁移率晶体管.这是迄今为止国内报道的截止频率最高的高电子迁移率晶体管.器件直流特性也很优异:跨导为980mS/mm,最大电流密度为870mA/mm.文中的材料结构和所有器件制备工艺均为本研究小组自主研制开发.     

功率增益截止频率为183GHz的In0.53Ga0.47As/In0.52Al0.48As HEMTs

通过合理的外延层材料结构设计和改进的器件制备工艺,制备出功率增益截止频率（fmax）为183GHz的晶格匹配InP基In0.53Ga0.47As-In0.52Al0.48As HEMT。该fmax为国内HEMT器件最高值,还报道了器件的结构、制备工艺以及器件的直流和高频特性。     

高电场下In0.53Ga0.47As／In0.52Al0.48As宽量子阱中11h激光电…

研究在外加电场０～５０ｋＶ／ｃｍ范围内，Ｉｎ０．５３Ｇａ０．４７ａｓ／Ｉｎ０．５２ａｌ０．４８宽量子阱电透射光谱中１１ｈ激子跃迁的谱线宽度（ＦＷＨＭ）。它可分解为由温度及界面粗糙度引起的非均匀展宽（高斯型）和由外场引起的均匀展宽（劳伦兹型）。用线性叠加的近似公式代替高斯和劳伦兹方程的卷积，再与实验光谱拟合。谱线总宽度Ｔ、高斯展宽成份ＴＧ及线性叠加系数η均作为拟合参数得到，从而可得劳伦兹展宽ＴＬ。将     

有效跨导为1052 mS/mm的高性能InP基In0.52Al0.48As/In0.53Ga0.47As HEMTs

我们成功研制了栅长为0.15 μm、栅宽为2?50 μm、源漏间距为2 μm 的InP 基In_0.52Al_0.48As/In_0.53Ga_0.47As高电子迁移率器件。室温下,当器件V_DS为1.7 V,V_GS为0.1 V时,其有效跨导达到了1052 mS/mm。传输线方法(TLM)测试显示器件的接触电阻为0.032 Ω.mm,器件欧姆接触电阻率为1.03?10_-7Ω.cm_-2. 正是良好的欧姆接触及其短的源漏间距减小了源电阻,进而使得有效跨导比较大。器件还有比较好的射频特性：当V_DS＝1.5 V, V_GS ＝0.1 V 时,f_T和f_max分别为151 GHz,303 GHz。文章报道的HEMT器件非常适合毫米波段集成电路的研制。     

T形栅In0.52Al0.48As/In0.6Ga0.4As MHEMTs功率器件

利用电子束光刻技术制备了200nm栅长GaAs基T型栅InAlAs/lnGaAs MHEMT器件.该GaAs基MHEMT器件具有优越的直流、高频和功率性能,跨导、饱和漏电流密度、阈值电压、电流增益截止频率和最大振荡频率分别达到510mS/mm,605mA/mm,-1.8V,138GHz和78GHz.在8GHz下,输人功率为-0.88(2.11)dBm时,输出功率、增益、PAE、输出功率密度分别为14.05(13.79)dBm,14.9(11.68)dB,67.74(75.1)%,254(239)mW/mm,为进一步研究高性能GaAs基MHEMT功率器件奠定了基础.     

T形栅In0.52Al0.48 As／In0.6Ga0.4As MHEMTs功率器件

利用电子束光刻技术制备了200nm栅长GaAs基T型栅InAlAs/InGaAs MHEMT 器件.该GaAs基MHEMT器件具有优越的直流、高频和功率性能,跨导、饱和漏电流密度、阈值电压、电流增益截止频率和最大振荡频率分别达到510mS/mm, 605mA/mm, -1.8V, 138GHz 和78GHz. 在8GHz下,输入功率为-0.88(2.11)dBm时,输出功率、增益、PAE、输出功率密度分别为14.05(13.79)dBm,14.9(11.68)dB,67.74 (75.1)%,254(239)mW/mm,为进一步研究高性能GaAs基MHEMT功率器件奠定了基础.     

120nm栅长In0.7Ga0.3As/In0.52Al0.48As HEMTs 器件

利用新型的PMMA/PMGI/ZEP520/PMGI四层胶T形栅电子束光刻技术制备出120nm栅长InP基雁配In0.7Ga0.3As/In0.52Al0.48As 高电子迁移率晶体管。制作出的InP基HEMT器件获得了良好的直流和高频性能,跨导、饱和漏电流密度、阈值电压、电流增益截止频率和最大单向功率增益频率分别达到520 mS/mm, 446 mA/mm, -1.0 V, 141 GHz 及 120 GHz。文中的材料结构和所有器件制备均为本研究小组自主研究开发。     

120-nm gate-length In0.7Ga0.3As/In0.52Al0.48As InP-based HEMT

120 nm gate-length In_(0.7)Ga_(0.3)As/In_(0.52)Al_(0.48) As InP-based high electron mobility transitions(HEMTs) are fabricated by a new T-shaped gate electron beam lithograph(EBL) technology,which is achieved by the use of a PMMA/PMGI/ZEP520/PMGI four-layer photoresistor stack.These devices also demonstrate excellent DC and RF characteristics:the transconductance,maximum saturation drain-to-source current,threshold voltage,maximum current gain frequency,and maximum power-gain cutoff frequency of InGaAs/I...     

Super-flat interfaces in In0.53Ga0.47As/In0.52Al0.48As quantum wells grown on (411)A InP substrates by molecular beam epitaxy

Effectively atomically flat interfaces over a macroscopic area (“(411)A super-flat interfaces”) were successfully achieved in In_0.53Ga_0.47As/In_0.52Al_0.48As quantum wells (QWs) grown on (411)A InP substrates by molecular beam epitaxy (MBE) at a substrate temperature of 570°C and V/III=6. Surface morphology of the In_0.53Ga_0.47As/In_0.52Al_0.48As QWs was smooth and featureless, while a rough surface of those simultaneously grown on a (100) InP substrate was observed. Photoluminescence (PL) linewidths at 4.2 K from the (411)A QWs with well width of 0.6–12 nm were 20–30 % narrower than those grown on a (100) InP substrate and also they are almost as narrow as each of split PL peaks for those of growth-interrupted QWs on a (100) InP substrate. In the case of the (411)A QWs, only one PL peak with very narrow linewidth was observed from each QW over a large distance (7 mm) on a wafer.     

Thermal stability of Al0.48In0.52As/Ga0.47In0.53As/InP heterostructure and its improvement by phosphidization

A drastic decrease in the sheet carrier concentration of modulation-doped Al_0.48In_0.52As/Ga_0.47In_0.53As/InP heterostructures has been observed after O₂ plasma treatment followed by thermal treatment up to 350°C. The decrease in sheet carrier concentration, which is speculated to be caused by both plasma damage and impurities penetrating from the surface of the epilayer, can be suppressed substantially by using PH₃ plasma treatment prior to the O₂ plasma and thermal treatments.     

Persistent photoconductivity and electron mobility in In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As/InP quantum-well structures

The influence of the width of the quantum well L and doping on the band structure, scattering, and electron mobility in nanoheterostructures with an isomorphic In_0.52Al_0.48As/In_0.53Ga_0.47As/In_0.52Al_0.48As quantum well grown on an InP substrate are investigated. The quantum and transport mobilities of electrons in the dimensionally quantized subbands are determined using Shubnikov-de Haas effect measurements. These mobilities are also calculated for the case of ionized-impurity scattering taking into account intersub-band electron transitions. It is shown that ionized-impurity scattering is the dominant mechanism of electron scattering. At temperatures T < 170 K, persistent photoconductivity is observed, which is explained by the spatial separation of photoexcited charge carriers.