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1.
《Electron Devices, IEEE Transactions on》1980,27(1):126-133
Related optical and detector properties of the PbS-Si heterojunction (HJ) are presented and discussed. A direct optical bandgap at 300 K of 0.44 eV has been measured for PbS-Si versus 0.42 eV for PbS-sapphire. The HJ photocurrent frequency response has been determined to consist of two waveform components: Type A, a "spike" present only during the turn-on and turn-off stages of a radiation pulse, is bias independent; Type B, a continuous response, which increases with reverse bias. The temperature characteristic of the photocurrent has been observed to be strongly dependent on which waveform type dominates. The HJ noise current is Johnson noise limited at zero bias and 1/f noise limited under reverse bias. The HJ dark current is postulated to have four main generation mechanisms depending on temperature: Si-generated current, diffusion current from the PbS, PbS depletion or surface-generation current, and surface leakage. The PbS-Si HJ spectral response combines the effect of intrinsic absorption in Si and PbS and transitions between the Si and PbS valence bands. A detectivity of 1 × 1011cm . Hz1/2/W has been obtained at 3 µm. 相似文献
2.
从理论上分析了用宽带隙材料作发射区的n-p-n光电晶体管可提高其发射区注入效率,就n-p-n光电三极管的增益特性进行了研究,给出了光增益与电增益的关系。 相似文献
3.
The formation and characteristics of a parasitic conduction band barrier located at a SiGe/Si heterojunction have been investigated using a commercial numerical simulator and a simple, three-region model of a heterojunction with a nearby p–n junction. The barrier’s formation is examined as a function of the displacement of the p–n junction from the heterojunction, but also found to depend on the germanium concentration, junction doping and the applied bias. The phenomenon is of interest for understanding the performance of SiGe/Si heterojunction bipolar transistors, where the p–n junction is intentionally displaced from the heterojunction at either the emitter or collector junctions or where boron outdiffusion from the base produces p–n junction displacement. The barrier is found to scale with the germanium mole fraction and to be significantly larger when the heterojunction is displaced into the p-side of the p–n junction. Beyond some minimum separation of the junctions, the barrier height rises with junction displacement and saturates. For a given displacement, the barrier’s height can be suppressed with reverse bias or enhanced by forward bias of the p–n junction. The results of the numerical simulations are compared with those from a simple analytical model as an aid in understanding the barrier’s formation and characteristics. 相似文献
4.
The barrier height of the manganite based p–n heterojunction is identified from the activation energy. The La0.35Pr0.32Ca0.33MnO3/Nb-doped SrTiO3 p–n heterojunction is fabricated by the pulse laser deposition technology. The junction shows good rectifying behavior which can be well described by the Shockley equation. A satisfactorily logarithmic linear dependence of resistance on temperature is observed, and also the relation between bias and activation energy (EA) deduced from the R−1/T curves is linear. As a result, the interfacial barrier of the heterojunction is obtained by extrapolating the Bias –EA plot to Y axis, which is 0.95 eV. 相似文献
5.
Y. M. Hsin H. T. Hsu K. P. Hseuh W. B. Tang C. C. Fan C. H. Wang C. W. Chen N. Y. Li 《Journal of Electronic Materials》2003,32(9):948-951
The effects of rapid thermal annealing (RTA) on InGaP/InGaAsN heterojunction bipolar transistors (HBTs) with a carbon-doped
base have been studied. The hydrogen and nitrogen concentrations in the base, as well as the direct current (DC) and radio
frequency (RF) device performance, were studied as a function of the annealing temperature. A 30-sec anneal at 650°C and 700°C
under N2 ambient effectively eliminates hydrogen from the base. As the annealing temperature is increased, the base sheet resistance
decreases, and the corresponding maximum frequency of oscillation increases. For all annealing temperatures studied, we found
degradation in the DC gain, presumably caused by the increase of nitrogen concentration in the base region. 相似文献
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7.
The properties of poly-Si/GaAs layered films on Si for use in wide bandgap emitters for Si heterojunction bipolar transistors
(Si-HBTs), were studied. A smooth GaAs film surface grown on Si was obtained at low temperature (200° C) from the initial
stage of growth. The x-ray diffraction (XRD) results indicated that strong GaAs orientation (111) was obtained for the poly-Si/GaAs/Si-substrate
layered structure after annealing at 800° C for 20 sec. Secondary ion mass spectroscopy (SIMS) profiles indicated that impurity
diffusion from the GaAs layer into the p-type Si substrate was negligible at 800° C. The electrical characteristics forn-poly-Si/n-GaAs/p-Si-substrate heterojunction diodes were also investigated. 相似文献
8.
Reactive ion etching (RIE) of bulk 4H-SiC based on CHF3-O2 plasma was studied by varying the rf power and process pressure. The elements on the etched surface and the surface roughness were characterized by Auger electron spectroscopy and atomic force microscopy, respectively. It was found that the surface roughening is mainly caused by Al contamination and C rich layer (C residues) induced micromasking effect. The micromasking effect is in turn determined by the dc self-bias developed at the substrates. A threshold dc self-bias exists at around −320 to −330 V, beyond which no micromasking effect was observed. This observation is explained in terms of physical ion bombardment and sputtering in the RIE process. 相似文献
9.
This paper presents the results of a simulation study focused on the evaluation of the DC characteristics of an n-p-n SiGe-based heterojunction bipolar transistor (HBT) performing an extremely thin n+ hydrogenated amorphous silicon (a-Si:H) emitter. The a-Si:H(n)/SiGe(p) structure exhibits an energy gap difference of approximately 0.8 eV mostly located at the valence band side and this results in an optimal configuration for the emitter/base junction to improve the emitter injection efficiency and thus the device performance.Considering a 20% Ge uniform concentration profile in the base region, simulations indicate that the DC characteristics of an a-Si:H/SiGe HBT are strictly dependent on two essential geometrical parameters, namely the emitter width and the base width. In particular, the emitter thickness degrades device characteristics in terms of current handling capabilities whereas higher current gains are obtained for progressively thinner base regions. A DC current gain exceeding 9000 can be predicted for an optimized device with a thin emitter and a 10 nm-thick, doped base. 相似文献
10.
K. F. Yarn Y. H. Wang M. P. Houng B. K. Lew 《International Journal of Electronics》2013,100(8):521-532
We will first derive a physics-based, analytical single-finger heterojunction bipolar transistor (HBT) model which takes into account the thermal effect. Next, the model is used to calculate the three figures of merit of HBT, i.e., current gain, cut-off frequency and maximum frequency. Their variation against the collector current density under the influence of thermal effect is presented and the calculation results are discussed. 相似文献
11.
C. H. Grein P. M. Young H. Ehrenreich T. C. McGill 《Journal of Electronic Materials》1993,22(8):1093-1096
Quantitative calculations are reported of both band-to band Auger and radiative recombination lifetimes in thin-layered type
II InxGa1−x Sb/InAs superlattices with energy gaps in the 5–17 μm range, using accurate band structure and numerical techniques. Results
for an 11 μm superlattice are compared with similar calculations for bulk HgCdTe and a HgTe/CdTe superlattice having the same
energy gap. The results show the n-type Auger rates to be comparable and the p-type rates to be suppressed by three orders
of magnitude in some experimentally realizable structures. Thus, well fabricated III–V superlattices appear to be excellent
candidates as a new class of infrarer detectors. 相似文献
12.
采用基于LMTO-ASA的平均结合能计算方法,研究了在ZnSxSe1-x衬底上沿(001)方向外延生长的应变层异质结ZnS/ZnSe的价带带阶值。研究表明,应变的结果使价带带阶随衬底组分(x)的变化呈非线性且单调的关系;与其他理论计算和实验结果比较,本文的计算结果比较理想。 相似文献
13.
Modeling of SiGe-base heterojunction bipolar transistor with gaussian doping distribution 总被引:2,自引:0,他引:2
The results of numerical modeling of the base transit time and collector current of SiGe-base heterojunction bipolar transistors with a Gaussian base doping profile and two Ge profiles (linearly graded and box) are presented for the first time. The importance of including the dependence of minority carrier mobility on the drift field and the dependence of the effective density of states on the Ge concentration along the base is demonstrated through the analysis of base transit time and collector current. A function describing the decrease of the density of states product in strained SiGe layers with increasing Ge concentration is proposed. 相似文献
14.
(111)-oriented BaF2 substrates were exposed to selenium vapor in an atmospheric pressure hydrogen ambient at three temperatures: 592, 629 and
696° C. Auger electron spectroscopy analysis of exposed surfaces showed formation of BaSe patches, BaSe layers, and BaSe3/BaSe composite layers at these three temperatures, respectively. We speculate that BaSe reaction layers form epitaxially
on BaF2 since cations in both materials have the same sublattice structure and the materials have a relatively small, 6 percent,
lattice parameter mismatch. Such structure-preserving substrate surface reactions can occur during IV-VI semiconductor epitaxy
on BaF2 and can play an important role in early stages of semiconductor growth. 相似文献
15.
Electronic synapses implementing in-memory computing system could overcome the developing limitation on the energy efficiency of traditional von Neumann architecture. Compared with the high sensitivity of biological synapses, lower responsivity of the memristive synapses was found via the electrical stimulations. Here, poly{2,2-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6- tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)-dithieno[3,2-b]thiophene-5,5-diyl-alt-thiophen-2,5-diyl} (PDPPBTT)/zinc oxide (ZnO) based heterojunction is found to exhibit stable memristive switching behavior, which originates from the confined formation/rupture of filament in the two-layer interface region as the ions migrate with different transport rates in two layers. The implementing synaptic functions in the sensitive memristive device can realize the short-term plasticity and long-term plasticity when stimulated by the applied electrical signals with different stimulating rate. Similar to the biological synapse, the memory loss, memory transition, and the critical role of stimulation rate on the transition process, can be achieved in the as-prepared memristor device. The systematic demonstrations on the synaptic emulation may facilitate building bio-inspired device-level neuromorphic systems. 相似文献
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17.
Shuai Yuan Qing‐Wei Liu Qi‐Sheng Tian Yan Jin Zhao‐Kui Wang Liang‐Sheng Liao 《Advanced functional materials》2020,30(12)
Perovskite‐based light‐emitting diodes (PeLEDs) have exhibited promising potential; however, their operational lifetimes are far from expectation. The large bias of the device during operation has been demonstrated as one of main reasons for accelerated device failure. To mitigate such a predicament, interfacial Auger effect (IAE) assisted sub‐bandgap voltage electroluminescence (EL) is a potential pathway to decrease the electric field intensity in each functional layer. However, the properties of a desirable IAE are still poorly understood. Herein, the underlying mechanism of IAE based on the injection characteristics of interfacial minority carriers at the Auger effect interface is investigated. Consequently, the prerequisites and the secondary conditions for the realization of IAE are proposed. Taking advantage of IAE assisted EL, the fabricated PeLEDs exhibit ultralow operational voltage, ignorable roll‐off, and improved operational stability. The findings in this work not only pave the way toward a feasible approach to enhance the stability of PeLEDs, but also highlight the potential of sub‐bandgap voltage EL in future display and lighting applications, especially in series circuits and tandem structures. 相似文献
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19.
镓铟砷/铝铟砷 QWLD中俄歇复合及其对T0的影响 总被引:2,自引:0,他引:2
修正了现行俄歇复合率的公式,并用之分析了晶格匹配GaInAs/AlInAs异质材料系统在有无量子尺寸效应情况下的俄歇复合随载流子浓度和温度变化的行为。发现其阈值电流密度随温度的变化行为可分为特征温度不同的相邻两个温区,在较高温区,量子尺寸效应作用不大,在较低温区,量子尺寸效应反而降低了T0,并对此意外的现象提出初步的解释。 相似文献
20.
SnO2/BiVO4 heterojunction composite photocatalysts with various mole ratios have been prepared via a simple hydrothermal method. The structure, composition and optical properties of the SnO2/BiVO4 composites were determined by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface analysis, X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). Photocatalytic activities of the composites were evaluated by studying the degradation of methylene blue (MB) solutions under simulated visible light irradiation (500 W halogen tungsten lamp). The 3:7 mol ratio SnO2/BiVO4 composite exhibited the highest photocatalytic performance, leading to 72% decompositon of MB within 120 min of irradiation. 相似文献