The electrical and dielectric characterization of the Co/ZnO-Rods/p-Si heterostructure depending on the frequency

Journal of Materials Science: Materials in Electronics - Zinc oxide (ZnO) rods film was fabricated by homemade and simple spray pyrolysis technique on a p-type silicon (Si) substrate, and the film...     

Photoelectric and electrical properties of a reverse-biased p-Si/n-CdS/n +-CdS heterostructure

We have demonstrated a photosensitive p-Si/n-CdS/n ⁺-CdS structure. A reverse bias voltage applied to this structure leads to electron injection from the narrow-band-gap material p-Si to the high-resistivity, wide-band-gap semiconductor n-CdS. Evidence is presented for mutual compensation of opposite drift and diffusion flows of charge carriers in this structure. At current densities in the range I ～ 10^?8 to 10^?7 A/cm², the opposite drift and diffusion flows of nonequilibrium minority charge carriers cause the photosensitivity of the structure to change sign in both the short- and long-wavelength regions of the spectrum. The mutual compensation of the opposite drift and diffusion flows at current densities on the order of ～10⁶ A/cm² leads to sublinear behavior of the reverse current-voltage characteristic in a wide range of bias voltages.     

New type of charged-particles detector based on point contacts formed in a GaAs-AlGaAs heterostructure by split-gates

We propose a new principle for a low temperature semiconductor detector of charged particles with possibly submicron lateral resolution based on point contacts formed in the 2-dimensional electron gas (2DEG) of a GaAs-Al_xGa_1-xAs heterostructure using split-gates. The detector operates up to liquid nitrogen temperatures. Impinging particles excite locally extra donors in the doping layer of the heterostructure. By measuring simultaneous increase in the conductances of 3 point contacts due to the impacts of charged particles the position of penetration is calculated using the Thomas-Fermi approximation for screening in 2DEG.     

A radio frequency single-electron transistor based on an InAs/InP heterostructure nanowire

We demonstrate radio frequency single-electron transistors fabricated from epitaxially grown InAs/InP heterostructure nanowires. Two sets of double-barrier wires with different barrier thicknesses were grown. The wires were suspended 15 nm above a metal gate electrode. Electrical measurements on a high-resistance nanowire showed regularly spaced Coulomb oscillations at a gate voltage from -0.5 to at least 1.8 V. The charge sensitivity was measured to 32 microe rms Hz(-1/2) at 1.5 K. A low-resistance single-electron transistor showed regularly spaced oscillations only in a small gate-voltage region just before carrier depletion. This device had a charge sensitivity of 2.5 microe rms Hz(-1/2). At low frequencies this device showed a typical 1/f noise behavior, with a level extrapolated to 300 microe rms Hz(-1/2) at 10 Hz.     

基于MEMS制作n-Zn0/p-Si异质结及特性

基于MEMS技术在P型<100>晶向双面抛光单晶硅片上制作c型硅杯,在C型硅杯上表面扩散P+,采用磁控溅射法在扩散区上制备择优取向为<0002>晶向的n-ZnO薄膜,形成n-ZnO/P-Si异质结.采用HP4280A型C-V特性测试仪分析n-ZnO/p-Si异质结的C-V特性,该异质结为突变结.采用HP4145B型半导体参数测试仪分析n-ZnO/p-si异质结,I-V特性,结果给出,n-ZnO/p-Si异质结在正向偏压下,电流随外加偏压按指数函数增加,反向电流不饱和,采用突变异质结的正反向势垒能带结构对其,I-V特性进行分析.     

Rapid photoelectric diagnostics of LEDs based on InGaN/GaN heterostructures

A new photoelectric method for rapid diagnostics of light-emitting diodes (LEDs) based on InGaN/GaN multiple quantum well (QW) heterostructures has been developed. An automated setup has been created for determining the arrangement of QWs in heterostructures, quality of interfaces, and degree of charge carrier localization in QWs using the results of room-temperature photoelectric measurements. The diagnostics of one heterostructure takes fractions of a second. The proposed method has advantages over the widely used technique based on the capacitance-voltage profiling of QW structures.     

Cooled photodiodes based on a type-II single p-InAsSbP/n-InAs heterostructure

Analysis of current-voltage and spectral characteristics of photodiodes based on a single p-InAsSbP/n-InAs heterostructure formed on a heavily doped n ⁺-InAs substrate (n ⁺ ～ 10¹⁸ cm^?3) is presented. It is shown that, at low temperatures (77 < T < 190 K), the generation-recombination current flow mechanism typical of p-i-n diodes dominates. Expected parameters of the photodiode that can be obtained using these heterostructures are presented.     

Ultrahigh sensitive near-infrared photodetectors based on MoTe2/germanium heterostructure

Nano Research - The efficient near-infrared light detection of the MoTe2/germanium (Ge) heterojunction has been demonstrated. The fabricated MoTe2/Ge van der Waals heterojunction shows excellent...     

New generation of highly stable high-temperature microelectromechanical transducers based on a silicon-on-isolator heterostructure

Some aspects are considered for creating a new generation of microelectromechanical transducers based on a silicon-on-isolator heterostructure with a monolithic integral tensoframe based on analyzing physicomechanical problems that restrain an increase in the technical level of semiconductor pressure transducers for information and control systems.     

Self-powered ultraviolet-blue photodetector based on GaN/double halide perovskite/NiO heterostructure

Journal of Materials Science - The stability and lead toxicity are two fundamental problems which might impede the application of halide perovskite photodetectors (PDs), and all-inorganic lead-free...     

Superluminescence in an AlGaAsSb/InGaAsSb/AlGaAsSb double heterostructure

Intense electroluminescence is observed for the first time in a AlGaAsSb/In_0.9Ga_0.1As_0.89Sb_0.21/AlGaAsSb double heterostructure in the 3–4 μm wavelength range at T=77 K. The structure was grown on a GaSb substrate by liquid-phase epitaxy. The photon energy at the maximum of the narrow emission band with a half-width of 9–10 eV is hv=387 meV which is 60 meV greater than the band gap of the narrow-gap InGaAsSb solid solution (E _g =326 meV). This behavior is attributed to the population inversion characteristics of the active region when an external bias is applied Pis’ma Zh. Tekh. Fiz. 23, 68–74 (May 12, 1997)     

XPS study of the a-C:H/Ti and a-C:H/a-Si interfaces

In this study ultrathin hydrogenated amorphous carbon (a-C:H) films have been grown onto the titanium and amorphous silicon (a-Si) overlayers by direct ion beam deposition using acetylene gas as a hydrocarbon source. X-ray photoelectron spectroscopy (XPS) was used for study of the DLC-Ti and DLC-Si interfaces. It was revealed that a-Si is a good interlayer for improvement of adhesion in the case of diamond-like carbon film deposition onto the steel substrate at room temperature. a-C:H film growth without substantial intermixing occurred on the a-Si. On the other hand, adhesion between the Ti interlayer and the diamond like carbon film was very sensitive to the deposition conditions (presence of the pump oil) as well as structure and stress level of the Ti film. It was explained by strong intermixing between the growing carbon film and Ti. Bad adhesion between the growing DLC film and Ti interlayer was observed despite formation of the TiC. At the same time, formation of the TiO_x was not an obstacle for good adhesion. It is shown that composition of the used hydrocarbon gas, structure of the Ti thin film and mechanical stress in it had greater influence on adhesion with a-C:H film than elemental composition of the Ti interlayer surface.     

Electrical characteristics of an organic thin copolymer/p-Si Schottky barrier diode

We have fabricated a poly(aniline-3-methyl thiophene) organic thin material on p-Si substrate by placing a solution of copolymer in acetonitrile on top of a p-Si substrate and then evaporating the solvent. The electrical and interface state density properties of the poly(aniline-3-methyl thiophene) copolymer/p-Si/Al diode have been investigated through methods using current-voltage (I-V), Cheung's, and a modified Norde's function. Good agreement was observed with the values of barrier height as obtained from all of these methods. The diode shows a non-ideal I-V behavior with an ideality factor greater than unity, which could be ascribed to the interfacial layer, interface states and series resistance. The interface state density of diode was determined using the forward-bias I-V characteristic technique at room temperature, and it decreases exponentially with bias from 1.39 × 10¹⁶ cm⁻² eV⁻¹ in (0.06 − E_v) eV to 4.86 × 10¹⁵ cm⁻² eV⁻¹ in (0.51 − E_v) eV.     

Infrared focal plane assemblies based on HgCdTe/Si(310) heterostructure

It is demonstrated for the first time that high-performance scanning infrared (IR) focal plane assemblies of the 288 × 4 format for long-wavelength (8–12 μm) IR spectral range can be created based on a Cd _x Hg_{1 − x} Te/Si(310) heterostructure.     

基于同步电感及buck-boost转换器的能量回收接口技术

设计基于同步电感及buck-boost转换器的接口技术—SCEI(Synchronous Charge Extraction and Inversion),完成该接口技术在恒定激振位移、恒定激振力情况下回收功率的理论分析及计算。理论计算表明,在恒定激振位移下忽略buck-boost转换效率时SCEI的回收功率大于Parallel-SSHI技术最大回收功率,且该回收功率与负载无关;在恒定激振力下SCEI回收功率与SECE技术特性相似;通过实验比较设计的SCEI技术与4种经典技术在相同激振位移下的回收功率。实验结果表明,SCEI技术回收功率约为SECE的1.5倍,且与负载无关。     

基于LabVIEW的DC/DC变换器自动测试系统

针对目前实验室DC/DC变换器测试项目增多、检测工作量大、较为繁琐且人为操作误差较大的现状,在LabVIEW环境下控制GPIB接口仪器开发了DC/DC变换器的自动测试系统(ATE).根据虚拟仪器的设计思想,把系统中具有各功能作用的仪器通过GPIB接口卡连接起来,在模块化、层次化的软件控制和处理下,自动实现DC/DC变换器直流、开关和交流三大类参数的测试和数据处理,结合具体型号的DC/DC变换器验证了ATE的功能实现.系统功能完善、操作简单、扩展性强,能很好满足DC/DC变换器测试的需要.     

Non-equilibrium crystallization-aggregation mechanism of a-C:H layer in a-C:H/a-Se complex films

Also representing: CCAST (World Laboratory), Beijing 100080, People's Republic of China and the Structure Research Laboratory, University of Sciences and Technology of China, Hefei 230026, People's Republic of China.     

Heterojunction photodetector based on graphene oxide sandwiched between ITO and p-Si

The drop casting method is utilized on indium tin oxide (ITO)-coated glass in order to prepare a sandwiched ITO/graphene oxide (ITO/GO) with silicon dioxide/p-type silicon (SiO₂/p-Si) heterojunction photodetector. The partially sandwiched GO layer with SiO₂/p-Si substrate exhibits dual characteristics as it showed good sensitivity towards the illumination of infrared (IR) laser at wavelength of 974 nm. Excellent photoconduction is also observed for current–voltage (I–V) characteristics at various laser powers. An external quantum efficiency greater than 1 for a direct current bias voltage of 0 and 3 V reveals significant photoresponsivity of the photodetector at various laser frequency modulation at 1, 5 and 9 Hz. The rise times are found to be 75, 72 and 70 μs for 1, 5 and 9 Hz while high fall times 455, 448 and 426 are measured for the respective frequency modulation. The fabricated ITO/GO-SiO₂/p-Si sandwiched heterojunction photodetector can be considered as a good candidate for applications in the IR regions that do not require a high-speed response.