长波红外材料n型Hg1—xCdxTe载波子寿命

测量了３种不同生长方法制备的长波红外碲镉汞晶体载流子寿命的温度变化关系,与窄禁带半导体载流子复合机构的理论计算结果比较表明,优质晶体中是以带间碰撞复合为主。     

长波红外n—HgCdTe材料的电阻比值与载流子寿命关系

少数载流子寿命是长波红外ＨｇＣｄＴｅ材料的重要性能参数。从大量实际数据统计中发现长波红外ｎ型ＨｇＣｄＴｅ材料的液氮温度电阻和室温电阻的比值与材料载流子寿命有定关系,电阻比值在２￣６之间有较大的载流子寿命值,而电阻比值大于１０的寿命值较小。     

用费米-狄拉克统计法计算Hg_(1-x)Cd_xTe本征载流子浓度

用费米-狄拉克统计法计算Hg_(1-x)Cd_x Te本征载流子浓度,以前是用玻耳兹曼统计法计算的。用玻耳兹曼统计法计算只限于组分x≥0.20的Hg_(1-x)Cd_xTe,而对于窄带隙组分x<0.20并不适用。我们使用下面两种方法改进现有计算:用组分和温度相关动量矩阵元的平方(这是对Kane的k·p理论的补充)和对除了Kane的理论所固有的那些近似值以外的能带结构不取近似值。我们发现,使用这两种统计法计算x≥0.20的结果都非常一致。我们还把计算结果与Hansen和Schmit的计算结果进行比较,发现在0.15≤x<0.40范围内十分一致。     

Hg_(1-x)Cd_xTe和Hg_(1-x)Zn_xTe的线性热膨胀系数

本文报道了有几种x值的Hg_(1-x)Cd_xTe(MCT)和Hg_(1-x)Zn_xTe(MZT)及其组成的二元化合物的热膨胀系数。膨胀系数的低温变化表明,与HgTe相比,MCT键参数变化很小,而对MZT,其键强度显著增加。     

绝缘体与Hg_(1-x)Cd_xTe界面特性

(Hg,Cd)Te光电器件的表面钝化工艺,特别是俘获电荷密度必须小于10~(11)cm~(-2)的长波光电二极管的有效钝化工艺,已探索了很长时间。这里存在两个难题:一是该材料对物理、化学处理的灵敏度问题,这将导致(Hg,Cd)Te表面化学配比发生变化和引起机械损伤;另一问题是它的热稳定性,这迫使我们进行低温钝化。很多资料证明,阳极化处理引起不能接受的高的固定电荷密度(～10~(12)cm~(-2)),这可能与半导体界面处发现的损伤层有关。本文简要介绍了这种或其他种类钝化剂的性质。     

用分子束外延法生长的Hg_(1-x)Cd_xTe制备的长波和中波红外光电二极管(上)

用分子束外延(MBE)生长的Hg_(1-x)Cd_xTe(0.20相似文献   

椭圆柱Bridgman炉生长Hg_(1-x)Cd_xTe晶体时固/液界面形状的数值模拟

用三维数值模拟方法研究了椭圆柱Ｂｒｉｄｇｍａｎ炉生长Ｈｇ１－ｘＣｄｘＴｅ晶体时固／液界面附近的温度分布，考察了安瓿位置、安瓿与炉膛直径相对大小以及炉膛温度分布等对固／液界面的影响情况．结果表明，椭圆柱Ｂｒｉｄｇｍａｎ炉内的特殊温度场分布有可能提高晶片上横向组分均匀性．     

两种不同方法测试HgCdTe材料少数载流子寿命

通过传统光电导衰退法和微波反射光电导衰退法两种方法对长波、中波及短波碲镉汞材料进行了载流子寿命测试,并对结果进行了比较。通过对比发现这两种方法测得的中波和短波材料的结果相差不大。但是对于长波材料,载流子寿命测试结果相差比较大,主要是因为长波材料寿命比较小,在相同的光激发条件下和偏流下,光电导灵敏度小,从而导致测出的信号小,在拟合的过程中偏差较大,导致载流子寿命相差较大。另外,用两种方法在同一短波材料的不同区域进行测试,传统光电导衰退法在材料电极附近测试结果明显偏小,电极区载流子寿命不到其他部分的50%。说明传统光电导衰退法测试载流子寿命受电极的影响比较大。     

外延和体生长Hg_(1-x)Cd_xTe位错对自扩散的影响

在250和400℃之间用放射示踪剂研究了Hg_(1-x)Cd_xTe的汞自扩散,发现扩散分布有两个分量,用接触式自动射线显迹法表明体晶样品的尾迹分量与通过位错排的短路扩散有关。用位错分析确定扩散的尾迹分布特性和在缺陷结构D_(Hg)内估计了汞扩散系数。在饱和汞分压下测量晶格扩散系数D_(Hg)=2×10~4exp{-1.1eV/kT}cm~2s~(-1)。外延样品扩散汞的表面浓度大约为体晶Hg_(1-x)Cd_xTe的1/40。     

n型HgCdTe晶片少子寿命分布的小光点测量

用聚焦的激光光点（宽度约为０．１ｍｍ）测量了ｎ型Ｈｇ１－ｘＣｄｘＴｅ（ｘ＝０．２）长条状薄片样品的少数载流子寿命沿样品长条方向的分布，结果表明分布是不均匀的，讨论了引起这种不均匀的可能原因。     

碲镉汞光化学氧化钝化及机理分析

采用光化学氧化钝化方法,首次实现了对n型碲镉汞光电导探测器的表面钝化;利用XPS分析了不同光化学氧化条件对氧化的影响及氧化物的构成,探讨了光化学氧化钝化的机理,并对光化学氧化钝化和阳极氧化的两类探测器性能进行了比较.     

MOVPE生长Hg1-xCdxTe薄膜的实验研究

采用金属有机化合物汽相外延法(MOVPE)和多层膜互扩散生长工艺(IMP)在不同的生长条件下生长了许多Hg1-xCdxTe/GaAs(211)薄膜样品,并对样品进行了傅利叶红外透射(FTIR)和范德堡Hall测量;通过对许多实验数据进行系统的对比分析,总结了薄膜的生长规律,并对这些生长规律作出了理论分析,阐释了薄膜的微观生长机制.     

Dark current suppression in HOT LWIR HgCdTe heterostructures operating in non-equilibrium mode

Typically,infrared detectors require cryogenic cooling to limit dark current w hich is directly dependent on Auger generation-recombination mechanism and highly influential in Hg Cd Te-narrow band gap material.The Auger suppressed architectures have an advantage over conventional detectors allow ing operation at elevated temperatures200 K.Architecture w ith combination of exclusion and extraction heterojunctions has been proposed to low er Auger contribution.The paper presents a new long-w ave(≈10μm)infrared Hg Cd Te architecture w ith graded gap/doping interfaces and extra barrier located in exclusion heterojunction to suppress dark current for high operating temperature conditions.Proper barrier implementation reduces dark current by more than 20 A/cm2for room temperature operation.     

加速坩埚旋转布里奇曼法碲镉汞晶体生长

叙述了采用加速坩埚旋转技术（ＡＣＲＴ）Ｂｒｉｄｇｍａｎ方法生长碲镉汞晶体的原理和方法。用这种技术生长的碲镉汞晶体的纵向和横向组分均匀性比常规Ｂｒｉｄｇｍａｎ生长方法有很大的改善，提高了用于制作平均探测率为８．０×１０＾１０ｃｍＨｚ＾１／２Ｗ＾－１的８元Ｓｐｒｉｔｅ探测器的晶片可用率。     

用微波反射法测HgCdTe中少数载流子寿命

介绍了用微波反射法测量ＨｇＣｄＴｅ中的少数载流子寿命,分析了其测量原理,并与接触式的光电导衰减法进行了比较。     

碲镉汞pn结中少数载流子寿命的测量

采用改进的光致开路电压衰退方法测量了不同组分Hg1-xCd,Te光伏探测器中光生少数载流子寿命。激发光源为脉冲YAG激光泵浦的光学参量产生器／放大器形成的可调谐红外脉冲激光器。为了减小结电容和串联电阻的影响,引入稳态背景光照明。用存储示波器记录pn结两端开路状态下的电压变化。从指数衰退的曲线经拟合得到开路电压的衰退时间常数,认为其反映了碲镉汞pn结中光生载流子的寿命。实验结果表明：四种组分的探测器在液氮温度下其少数载流子寿命值范围在18—407ns之间。     

Advances in large-area Hg1−xCdxTe photovoltaic detectors for remote-sensing applications

State-of-the-art large-area photovoltaic (PV) detectors fabricated in HgCdTe grown by molecular beam epitaxy (MBE) have been demonstrated for the Crosstrack Infrared Sounder (CrIS) instrument. Large-area devices (1 mm in diameter) yielded excellent electrical and optical performance operating at 81 K for λ_c ∼ 15 μm, at 98 K for λ_c ∼ 9 μm, and λ_c ∼ 5-μm spectral cutoffs. Fabricated detectors have near-theoretical electrical performance, and Anti Reflection coated quantum efficiency (QE) is greater than 0.70. Measured average R₀A at 98 K is 2.0E7 Ωcm², and near-theoretical QEs greater than 0.90 were obtained on detectors with λ_c ∼ 5-μm spectral cutoffs. These state-of-the-art large-area PV detector results reflect high-quality HgCdTe grown by MBE on CdZnTe substrates in all three spectral bands of interest.     

Metalorganic vapor phase epitaxyin-situ growth of p-on-n and n-on-p Hg1-xCdxTe junction photodiodes using tertiarybutylarsine as the acceptor source

We report arsenic doping of Hg_1-xCd_xTe (0.2 < x < 0.3) grown using metalorganic vapor phase epitaxy (MOVPE) by the direct alloy growth (DAG) technique. Tertiarybutylarsine (TBAs) was used as a precursor for As doping. Several epilayers were grown at different Hg partial pressures and TBAs bubbler temperatures in order to study the doping characteristics. The amount of As incorporated in the layer as well as the acceptor concentration were found to be a strong function of the Hg pressure. Secondary ion mass spectrometric studies on heterostructures showed that the compositional interdiffusion is less than the diffusion of As during growth. P-N junctions were grown using TBAs for the first time and several of these layers were processed to fabricate photodiodes. A p-on-n grown junction photodiode with a cutoff wavelength of 8.2 μm had an R_oA value of 241 ohm-cm² at 80K and is the highest reported value for p-on-n DAG-MOVPE devices. Methods to improve the device R_oA of the grown junctions are also proposed.