掺铥光纤纤芯掺杂浓度与吸收系数实验研究

以掺铥双包层光纤为例,主要介绍了用高温气相掺杂工艺制备高掺铥双包层光纤的工艺原理和工艺过程,对不同料路温度下铥的掺杂浓度进行了研究,重点研究了纤芯掺杂浓度与吸收系数的关系,通过研究找到了相关规律,为采用高温气相掺杂工艺制备高掺铥双包层光纤提供了依据.     

准共线声光可调谐掺铒光纤激光器的研究

提出了一种新颖的单纵模、单偏振的可调谐掺铒光纤激光器结构。使用准共线型声光可调谐滤波器作为调谐元件。利用饱和吸收效应在未泵浦低掺铒光纤中形成自写入瞬态光栅,用以压窄输出激光的线宽,并且有效地防止跳模。理论计算表明:当泵浦功率为100mW时,激光器的输出功率可达5.5mW,输出线宽在10-4nm量级。这些数据对后续的实验研究有指导作用。     

Performance improvement mechanisms of organic thin-film transistors using MoOx-doped pentacene as channel layer

Organic thin-film transistors (OTFTs) with various MoO_x-doped pentacene channel layers were fabricated and investigated. Compared the OTFTs with the 0.50 mol% MoO_x-doped pentacene to the conventional OTFTs without MoO_x dopant, the maximum output current was increased from −11.6 to −37.9 μA, the effective field-effect mobility was enhanced from 0.71 to 1.60 cm²/V-s, the threshold voltage was reduced from −21.2 to −14.8 V, and the on/off current ratio slightly decreased from 3.6 × 10⁶ to 1.2 × 10⁶. The performance improvement was attributed to the highest occupied molecular orbital (HOMO) of the MoO_x-doped pentacene gradually approached to the Au work function with increasing the doping percentage of MoO_x, which led to reduce the contact resistance and to enhance the p-type characteristics of the MoO_x-doped OTFTs by increasing the hole density and enhancing the hole-injection efficiency. However, the output current and the field-effect mobility decreased with an increase of the MoO_x doping percentage, if the doping mole percentage of MoO_x was higher than 0.50%. This behavior was attributed to the Fermi level pinning effect, gradual increase of hole concentration and significant degradation of crystallinity.     

掺碳GaAs生长特性的研究

采用以碳纤维为碳源的固态源MBE技术，生长了不同厚度的重接碳GaAs以及具有不同表层厚度的δ碳掺杂GaAs，通过Nomarski干涉显微镜和原子力显微镜（AFM）对样品表面形貌的观察，分析了挨碳GaAs的生长过程和各种缺陷的产生，提出碳的掺入导致了GaAs材料的三维岛状生长，促进了各种缺陷的力生。提出了通过改善生长条件减少缺陷的途径。     

Yb3+掺杂铋酸盐玻璃的低温发光特性

选取55Bi2O3-25B2O3-10SiO2-7Ga2O3-3Yb2O3系统铋酸盐玻璃,研究了在不同温度(9-350 K)下Yb3+离子的发射光谱和荧光寿命变化情况,计算了不同温度下Yb3+离子在976和1020 nm的有效线宽△λeff,比较了不同温度下Yb3+离子的光谱特性和荧光寿命变化情况.发现随着测试温度的降...     

Er^3＋掺杂玻璃的1．5μm发射光谱及其带宽

用高温熔融法制备了Er^3 掺杂的氧化物玻璃，研究了Er^3 在11～300K温度范围内对应于^4I13/2→^4I15/2跃迁的1．5μm发射光谱，将^4I13/2多重态中的高能态和最低能态向基态跃迁发射的光谱成分从测量的发射光谱中分离开来，讨论了光谱成分对1．5μm发射带宽的影响。提出了等效四能级模型，并用此模型解释了Er^3 ^4I13/2→^4I15/2辐射跃迁的线形及其变温特性。分析表明，提高^4I13/2多重态中高能态的辐射跃迁几率是获得室温下宽带1．5μm发射的关键。最后，根据Mc Cumber理论，利用吸收光谱变换得到了与测量一致的发射光谱形状及相应的受激发射截面。     

掺钕保偏光纤激光器腔内倍频实验研究

从双包层光纤激光器的速率方程和光传输方程出发,数值模拟得到泵浦功率20 W时最佳增益光纤长度。在此基础上,采用线型直腔结构,通过透镜耦合的方式,用808 nm半导体激光器对掺Nd3+熊猫型保偏双包层光纤进行端面泵浦,获得1060 nm连续偏振的基频光输出,其线宽小于5 nm,光-光转换效率达到50%;之后,采用腔内插入KTP晶体的方式对基频光进行倍频获得530 nm的绿光输出,其线宽小于3 nm,倍频效率达到20%。在20 W的入纤功率泵浦下,得到2 W的530 nm连续绿光输出。     

calculations of p-type δ-doped quantum wells in Si

We present the hole subband structure calculation in single and double p-type δ-doped quantum wells in Si based on the 4×4 Luttinger–Kohn Hamiltonian. The valence band bending and the Γ hole states are calculated within the lines of the Thomas–Fermi–Dirac approximation and the effective mass theory at the Brillouin zone center. The obtained zone center eigenstates are then used to diagonalize the k·p Hamiltonian for non-zero k. The hole subband structure is analyzed as a function of the impurity density and the distance between δ wells. It is shown that the application of a 4×4 model to describe the hole ground state in single p-type δ-doped in Si can be misleading.     

废旧锂离子电池水热法制备钕掺杂钴铁氧体

以废旧锂离子电池为原料,采用水热法制备了Nd3+掺杂的钴铁氧体。并用XRD和振动样品磁强计(VSM)研究了Nd3+的掺杂量对钴铁氧体的相结构和磁性能影响。结果表明:所有产品均呈尖晶石结构,当掺杂的Nd3+摩尔分数为1.0%时,产品具有较好的磁性能。产品的Ms为3.954×105A/m,Mr为1.954×105A/m,Hc为82.47kA/m。     

Ce3+掺杂SnO2纳米带对乙二醇的气敏特性研究

采用热蒸发气相沉积法,以An为催化剂成功制备了Ce3+掺杂的SnO2纳米带.用X射线衍射(XRD)、扫描电子显微镜(SEM)、光电子能谱(EDX)对样品的形貌、结构和成分进行了表征分析.结果表明:Ce3+掺杂的SnO2纳米带具有金红石结构,纳米带表面光滑、平整,结晶良好,其成分由Ce,Sn和O构成.同时,研究了单片Ce3+掺杂的SnO2纳米带对丙酮、乙醇和乙二醇的气敏特性,发现温度为190℃时器件对乙二醇气敏响应最强,选择性也最好.Ce3+掺杂的SnO2纳米带对乙二醇响应、恢复时间短,可逆性好,适合在较宽浓度范围对乙二醇气体进行检测.