非晶硅集成型色敏元件及其传感器

研究了一种新型的非晶硅ＰＩＮ异质结集成型色敏元件及其传感器的制备工艺和结构，详细讨论了色敏元件的优化设计以及响应特性、暗电流等性能。     

C60半导体光电器件

讨论了两类Ｃ６０薄膜作为畔导体材料制备的光电器件：Ｃ６０电致发光二级管和半导体聚合物／Ｃ６０导质结二极管、分析了器件的工作原理、指出了Ｃ６０作为半导体光电材料潜在的应用领域。     

Si／SiGe／Si HBT的优化设计

给出了常温和低温Ｓｉ／ＳｉＧｅ／ＳｉＨＢＴ的设计原则，并进行了讨论。指出了低温和室温ＨＢＴ设计上的差异。这些原则可用于设计特定要求的Ｓｉ／ＳｉＧｅ／ＳｉＨＢＴ。     

Effect of edges on the reliability of GaAs and (AlGa) as heterojunction leds

The effect of various diode geometries on the degradation rate of heterojunction diodes with either GaAs or (AlGa)As in the recombination region has been studied. It is shown that GaAs diodes are particularly sensitive to edge-related degradation which varies with the current density J as J^3/2. The addition of Al to the recombination region considerably reduces the degradation rate of diodes both with and without exposed edges, and data are reported for Al_0.1Ga_0.9As stripe-contact edge-emitting structures operating for over 20,000 hours with no change in output at 1000 A/cm².     

InGaAs/InGaAsP/InP SAGM-APD器件设计考虑及I_P—V曲线二级阶梯状扭折

本文根据雪崩电场和限制隧道电流电场要求出发,设计和估算了InGaAs/InGaAsP/InPSAGM-APD器件参数,测量并解释了I_p-V曲线的二级阶梯扭折行为,指出了V_(th)/V_B以1/3左右为宜和与实际测量的M_p比较吻合的经验公式。     

Heterojunction solar cells of SnO2/Si

Heterojunction solar cells (HJSC’s), fabricated by electron beam evaportaion of SnO₂ films onto monocrystalline and polycrystalline Si substrates, show conversion efficiencies as high as 9.9%, fill factors of 0.64, and open circuit voltages of 525 mV under AMI simulated irradiation. The SnO₂, an n-type semiconductor, acts as a transparent window to solar irradiation and as an antireflection coating of the Si, and it provides the band bending in the Si necessary for photovoltaic conversion. The SnO₂ films, nominally 50 nm thick, have conductivities of the order of 10³(Ω-cm)⁻¹ so that the film makes a good electrical contact between the junction and the metallic front contacts. Measurements of C⁻²-V and I-V characteristics are consistent with heterojunction theory, and the data imply an electron affinity of the SnO₂ of approximately 0.8 eV greater than the electron affinity of Si. This value limits the open circuit voltage of HJSC’s made on p-type substrates to values too small for useful photovoltaic conversion. The predominant dark current mechanism of units of n-type substrates at room temperature and forward bias in the range of 0.3−0.5 V is electron-hole recombination in the transition region. The experimentally determined activation energy is 0.51 eV, approximately E_g/2. At forward voltages below 0.3 V, multistep tunneling via interband states predominates. The photocurrent apparently depends on interface states through which the photogenerated holes in the Si recombine with electrons in the SnO₂.     

Evaluation of InP-to-silicon heterobonding

In this paper, we evaluate hydrophilic (HP) and hydrophobic (HB) surface pre-treatments in InP-to-Si direct wafer bonding. Surface roughness and surface chemistry was examined using atomic force microscopy and X-ray photoelectron spectroscopy, respectively. After bonding, the bonded interfaces were evaluated using infrared transmission imaging, bond-strength and current–voltage (I–V) measurements. It was found that HP surface treatment using oxygen plasma makes room temperature bonding of InP and Si very spontaneous, and results in high bond-strengths already after low-temperature annealing. This was not observed when using standard oxidising acids as HP surface treatment before bonding. HB InP and Si surfaces, also, did not prove to bond spontaneously at room temperature and the bond-strength started to increase only after annealing at about 400°C. HB bonding and annealing at 400°C was though the best choice regarding the electrical characteristics of the bonded InP/Si heterojunction.     

Modelling of SiGe heterobipolar transistors: 200 GHz frequencies with symmetrical delay times

Our basic approach is to develop a symmetrical design with equal delay times for collector, base and the total load to simulate the high frequency behaviour of SiGe heterobipolar transistors (HBTs). On this base we have investigated the feasibility of SiGe HBTs with transit frequencies f_T above 200 GHz. A symmetrical design reaching f_T=208 GHz is presented. The dependence of the high frequency behaviour on Ge content and vertical transistor design is shown. Critical parameters like the maximum current density and the breakthrough voltage are considered. An analytical model is compared to numerical simulations and experimental data.     

Simplified Method of Valence Band Offset Calculation at Strained Layer Heterojunction

The average bond energy method is popularized and applied to study band offsets at strained layer heterojunctions.By careful examination of hydrostatic and uniaxial strain actions on the band offset parameter Emv,it is found that the average band offset parameter Emv,av=Em-Ev,av remains basically unchanged under different strain conditions.Therefore,provided the band offset parameter before strain Emv,0 of bulk material is calculated,and the experiment values of deformation potential b and spin-orbit(SO)splitting energy △0 are quoted,the Emv at strained layer can be obtained by a simple and convenient algebraic calculation.Thus the valence band offset △Ev at strained layer heterojunctin can also be predicted conveniently.This simplified calcultation method is characterized by decreased calculation amount and increased conviction due to use as many as possible the experiment values.     

A photovoltaic cell from p-type boron-doped amorphous carbon film

Boron-doped amorphous carbon (a-C(B)) films were prepared on n-type silicon using pulsed laser deposition technique of a graphite target. The a-C(B) films have been proved to be p-type by the formation of a heterojunction between the a-C(B) film and n-Si. The device of a-C(B)/n-Si structure yielded an open-circuit voltage (V_oc) of 0.27 V and a short-circuit current density (J_sc) of 2.2 mA/cm² under illumination (AM1.5 100 mW/cm²). According to calculation, the energy conversion efficiency and fill factor were found to be about 0.3% and 0.53, respectively.