电极材料对肖特基结β辐射伏特同位素电池性能的影响

肖特基结β辐射伏特同位素电池的换能单元由金属电极层和半导体层组成,金属电极层材料的选择对提高电池输出性能有重要的影响.目前,肖特基金属电极材料多集中于Au和Ni两种金属,尚未对不同金属电极材料进行系统的分析对比.针对不同电极材料导电性能的差异,引入电子传输效率因子,从理论上分析对比了Al、Au、Cu、Ni和石墨烯5种电...     

β辐射伏特效应电池内建电场厚度设计

计算了放射源在半导体中沿厚度方向的能量沉积,并以此计算β辐射伏特效应电池的理想短路电流。通过对比实测短路电流和理想短路电流可以得到β辐射伏特效应电池PN结内建电场的扩散长度。在上述基础上,本文给出了β辐射伏特效应电池内建电场厚度设计原则： 放射源在半导体中能量沉积厚度和PN结内建电场中载流子的扩散长度两者中较小的应作为β伏特效应电池内建电场厚度设计值,如果沉积厚度远远大于载流子扩散长度,则说明多结结构较适合该类β伏特效应电池果,多结的结数应约为沉积厚度与载流子扩散长度的比。     

石墨烯/CdTe肖特基结柔性薄膜太阳能电池研究

利用Matlab仿真模拟了石墨烯/P-CdTe肖特基结太阳能电池的光电特性。结果表明,电池的短路电流密度Jsc为23.9×10–3A/cm2、开路电压Voc为0.64 V、填充因子FF为79.0,转换效率η高达12%。与传统的氧化铟锡(ITO)电极比较,石墨烯柔韧性好,同时具备高透光和高导电的特性,可替代ITO作为新型电极材料来制备柔性薄膜太阳能电池。     

4H-SiC肖特基微型同位素电池(英文)

半导体同位素电池由于其寿命长、集成性优良、环境适应性强等特点成为解决MEMS能源问题的理想手段。利用4H-SiC材料的宽禁带特性,制造了4H-SiC肖特基同位素电池。对电池的耗尽层厚度以及掺杂浓度进行了优化设计,对肖特基金属进行了选择。使用4mCi/cm2的63Ni作为同位素电池的放射源对制造的同位素电池进行了测试。测试结果表明,该同位素电池可以获得31.3nW/cm2的功率密度、0.5V的开路电压、3.13×10-8A/cm2的短路电流密度和1.3%的转换效率。将电池的输出特性和硅基的平板型、3D结构电池输出特性进行了比较,证明4H-SiC肖特基同位素电池能够获得较高的功率密度。电池的性能可通过提升势垒高度、提高工艺质量、更换同位素等方式得到提高。     

基于InAs/GaAs量子点-石墨烯复合结构的肖特基光电探测器研究

石墨烯具有电子迁移率高、透过率高(T≈97.7%)且费米能级可调的特性。砷化镓的电子迁移率比硅的大5到6倍。引入砷化铟量子点后,光电探测器具有低暗电流、高工作温度、高响应率和探测率的特点,因而可被用于制备响应快、量子效率高和光谱宽的光电探测器。对基于InAs/GaAs量子点-石墨烯复合结构的肖特基结的I-V特性和光电响应进行了研究。结果表明,在0 V偏压下,该器件在400 nm～950 nm均有响应,峰值响应率可达0.18 A/W;在反向偏压下,器件的峰值响应率可达到0.45 A/W。通过对暗电流随温度变化的特性进行分析,得到了InAs/GaAs量子点-石墨烯肖特基结在室温附近以及80 K附近的势垒高度。     

迭加原理的错误及纠正—评PN结光生伏特效应

本文纠正了“迭加原理”的错误,建立了新的光伏理论。     

基于石墨烯/铟砷量子点/砷化镓异质结新型光电探测器

研究了一种石墨烯/铟砷量子点/砷化镓界面形成的异质结探测器的暗电流特性以及光电响应性质.虽然石墨烯具有很高的电子迁移率,但受限于较低的光子吸收率,使其在光电探测领域的应用受到了限制.而半导体量子点具有量子效率高,光吸收能力强等独特优点.于是利用石墨烯-砷化铟量子点-砷化镓异质结结构制备了一种新型光电探测器.并对该探测器的响应率、I-V特性曲线、暗电流特性、探测率、开关比等关键性能进行了研究.其在637 nm入射光情况下的响应率、探测率以及开关比可分别达到为17. 0 m A/W、2. 3×10~(10)cm Hz~(1/2)W~(-1)和1×10~3.而当入射光为近红外波段的940纳米时,响应率进一步增加到了207 m A/W.同时,还证实了该器件的暗电流、肖特基势垒高度和理想因子对温度的都具有较高的依赖性都较强.     

Au-GaN肖特基结的伏安特性

在MBE和MOCVD两种方法制备的n-GaN材料上制作了Au-GaN肖特基结,测定了肖特基结的室温I-V特性.分析表明：GaN材料的载流子浓度对肖特基结的特性有很大的影响     

Au-GaN肖特基结的伏安特性

在 MBE和 MOCVD两种方法制备的 n- Ga N材料上制作了 Au- Ga N肖特基结 ,测定了肖特基结的室温 I- V特性 .分析表明 :Ga N材料的载流子浓度对肖特基结的特性有很大的影响     

三结GaAs电池损伤对输出特性的影响研究

针对发生损伤后三结GaAs电池的电学特性进行了研究。从三结电池的等效电路模型出发,根据光伏效应相关理论,建立了GaAs三结电池损伤分析模型,具体计算了损伤发生在不同位置时,光电池输出电压、功率、效率的变化。结果表明,顶结发生热熔损伤对电池的电学特性影响最大,将直接导致光电转换效率下降17.23%。中结发生热熔损伤对电池的电学特性影响次之,将引起4.23%的效率下降。底结损伤对电池的电学特性影响相对最小,所导致的光电转换效率下降量为2.42%。     

Strain Modulation in Graphene/ZnO Nanorod Film Schottky Junction for Enhanced Photosensing Performance

Strain modulation in flexible semiconductor heterojunctions has always been considered as an effective way to modulate the performance of nanodevices. In this work, a graphene/ZnO nanorods film Schottky junction has been constructed. It shows considerable responsivity and fast on‐off switch to the UV illumination. Through utilizing the piezopotential induced by the atoms displacement in ZnO under the compressive strain, 17% enhanced photosensing property is achieved in this hybrid structure when applying ?0.349% strain. This performance improvement can be ascribed to the Schottky barrier height modification by the strain‐induced piezopotential, which results in the facilitation of electron–hole separation in the graphene/ZnO interface. An energy band principle as well as a finite element analysis is proposed to understand this phenomenon. The results here provide a facile approach to boost the optoelectronic performance of graphene/ZnO heterostructure, which may also be applied to other Schottky junction based hybrid devices.     

Direct Growth of Nanocrystalline Graphene/Graphite Transparent Electrodes on Si/SiO2 for Metal‐Free Schottky Junction Photodetectors

Conventional methods to produce graphene/silicon Schottky junctions inevitably involve graphene transfer and metal deposition, which leads to the techniques being complicated, high‐cost, and environmentally unfriendly. It is possible to directly grow hybrid nanocrystalline graphene/graphite transparent electrodes from photoresist on quartz without any catalyst. Due to the source material being photoresist, nanographene/graphite patterns can easily be made on Si/SiO₂ structures to form nanographene/silicon Schottky junctions via commercial photolithography and silicon techniques. The obtained Schottky junctions exhibit excellent properties with respect to photodetection, with photovoltage responsivity of 300 V W^‐1 at a light power of 0.2 μW and photovoltage response time of less than 0.5 s. The devices also exhibit an excellent reliability with the photovoltage deviating less than 1% when cycled over 200 times.     

Characteristics of Schottky Barrier Junction Based on Hexagonal Microtube ZnO

Hexagonal microtube ZnO was firstly grown on single crystal p-Si (111) substrates by hydrothermal method, and fabricated Ag/n-ZnO and Au/n-ZnO Schottky junction. Schottky effective barrier heights were calculated by I-V measurement. It is confirmed that the presence of a large amount of surface states related possibly to lattice imperfections existed near the surface leads to the pinning of the surface Fermi level at 0.35 eV below the conduction-band edge. Then the fabricated Schottky barrier junctions are evaluated for their use as UV photodetectors.     

Kinetic Isotope Effect in the Hydrogenation and Deuteration of Graphene

Time‐dependent photoemission spectroscopy is employed to study the kinetics of the hydro‐genation/deuteration reaction of graphene. Resulting in an unusual kinetic isotope effect, the graphene deuteration reaction proceeds faster than hydrogenation and leads to substantially higher maximum coverages of deuterium (D/C≈35% vs H/C≈25%). These results can be explained by the fact that in the atomic state H and D have a lower energy barrier to overcome in order to react with graphene, while in the molecular form the bond between two atoms must be broken before the capture on the graphene layer. More importantly, D has a higher desorption barrier than H due to quantum mechanical zero‐point energy effects related to the C–D or C–H stretch vibration. Molecular dynamics simulations based on a quantum mechanical electronic potential can reproduce the experimental trends and reveal the contribution of the constituent chemisorption, reflection, and associative desorption processes of H or D atoms onto graphene. Regarding the electronic structure changes, a tunable electron energy gap can be induced by both deuteration and hydrogenation.     

Comprehensive Pyro‐Phototronic Effect Enhanced Ultraviolet Detector with ZnO/Ag Schottky Junction

As a coupling effect of pyroelectric and photoelectric effect, pyro‐phototronic effect has demonstrated an excellent tuning role for fast response p–n junction photodetectors (PDs). Here, a comprehensive pyro‐phototronic effect is utilized to design and fabricate a self‐powered and flexible ultraviolet PD based on the ZnO/Ag Schottky junction. By using the primary pyroelectric effect, the maximal transient photoresponsivity of the self‐powered PDs can reach up to 1.25 mA W^?1 for 325 nm illumination, which is improved by 1465% relative to that obtained from the steady‐state signal. The relative persistent secondary pyroelectric effect weakens the height of Schottky barrier, leading to a reduction of the steady‐state photocurrent with an increase in the power density. When the power density is large enough, the steady‐state photocurrent turns into a reverse direction. The corresponding tuning mechanisms of the comprehensive pyro‐phototronic effect on transient and steady‐state photocurrent are revealed based on the bandgap diagrams. The results may help us to further clarify the mechanism of the pyro‐phototronic effect on the photocurrent and also provide a potential way to optimize the performance of self‐powered PDs.     

Near‐Infrared Light Photovoltaic Detector Based on GaAs Nanocone Array/Monolayer Graphene Schottky Junction

Near infrared light photodiodes have been attracting increasing research interest due to their wide application in various fields. In this study, the fabrication of a new n‐type GaAs nanocone (GaAsNCs) array/monolayer graphene (MLG) Schottky junction is reported for NIR light detection. The NIR photodetector (NIRPD) shows obvious rectifying behavior with a turn‐on voltage of 0.6 V. Further device analysis reveals that the photovoltaic NIRPDs are highly sensitive to 850 nm light illumination, with a fast response speed and good spectral selectivity at zero bias voltage. It is also revealed that the NIRPD is capable of monitoring high‐switching frequency optical signals (～2000 Hz) with a high relative balance. Theoretical simulations based on finite difference time domain (FDTD) analysis finds that the high device performance is partially associated with the optical property, which can trap most incident photons in an efficient way. It is expected that such a self‐driven NIRPD will have potential application in future optoelectronic devices.     

快热退火对Co/n-Poly-SiGe肖特基结I-V-T特性的影响

采用射频磁控溅射法在n-Si(100)衬底上沉积Si1-xGex薄膜,俄歇电子谱(AES)测定Si1-xGex薄膜的Ge含量约为17%。对薄膜进行高温磷扩散掺杂,制得n-poly-Si0.83Ge0.17。在n-poly-Si0.83Ge0.17薄膜上溅射一层Co膜,制成Co/n-poly-Si0.83Ge0.17/n-Si肖特基结样品。在300～600℃范围内,对样品做快热退火。对不同退火温度下的样品做I-V-T测试。研究发现,测试温度升高,不同退火温度样品的肖特基势垒高度(SBH)的差别变小,500℃退火的样品,表观SBH最小。总体上,SBH随测试温度的升高而变大,理想因子的变化趋势则与之相反。基于SBH的不均匀分布建模,对实验结果给出了较为合理的解释。