【作者】 冯伟；

【导师】 胡平安；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2017， 博士

【摘要】 二维层状半导体材料表现出不同于块体材料的物理和化学性质,在纳米电子器件和纳米光电子器件领域具有巨大的应用前景,因此成为材料和微电子等领域的研究热点。然而稳定的、高性能的二维层状半导体材料还有待进一步探索。硒化铟（InSe和In₂Se₃）是典型的IIⅠ-ⅤI族层状半导体材料,块体硒化铟表现出良好的稳定性、高的电子迁移率和高的光吸收效率,可以应用于高性能电子和光电子器件。目前关于二维硒化铟薄膜的研究甚少,很多性能还有待开发。本文探索了二维硒化铟薄膜的制备方法,并构筑了多层InSe场效应晶体管和光电晶体管,研究了多层InSe电子输运性质和光探测性能。制备了InSe-CuInSe₂平面p-n异质结,研究了其电学和光伏性能。构筑了二维In₂Se₃薄膜的力学传感器件和电子皮肤器件,系统研究了其对人体活动的监测性能。本文通过机械剥离法,在不同衬底成功制备二维β-InSe薄膜,并揭示了InSe薄膜厚度对拉曼光谱和荧光光谱的影响规律。构筑了多层InSe场效应晶体管并研究了其电学输运性质,得到了媲美单晶硅器件的性能。铝、钛、铟和铬四种金属接触电极的InSe场效应晶体管的电学输运性能与四种金属功函数大小顺序不一致,与四种金属在InSe表面的表面粗糙度一致。实验和理论模拟结果证明金属d轨道电子的数量决定了金属与二维InSe接触电阻的数值,金属铬是较好的电极材料。施加正负栅极电压,在常压和真空条件下多层InSe场效应晶体管的表现出不同的不稳定性。实验结果说明栅极电压诱导的不稳定性主要源自栅极电压可以调控InSe表面的氧气和水分的吸附和解吸过程。比较不同介电层InSe场效应晶体管的电学输运性能,发现PMMA/氧化物双介电层结构显著提高InSe的电学输运性能。表面粗糙度和接触角测试结果证实PMMA/氧化物双介电层可以有效屏蔽氧化物介电层表面产的库仑杂质散射和极性声子散射。建立了多层InSe的多次吸收反射的光吸收模型,构筑了多层InSe光电晶体管并研究了光探测能力。理论模拟说明InSe对光的吸收与厚度紧密相关,呈现非线性关系。InSe光电晶体管在不同波长和光照强度条件下激发,表现出宽的光谱探测区间,计算的光响应值和光探测值曲线证明该光电探测器具有超高的光电探测能力。多次弯曲后,柔性透明InSe薄膜光电探测器表现出良好的稳定性。发展了简单固相法制备二维InSe-CuInSe₂平面p-n异质结的新方法,并研究了该异质结的电学和光电转化性能。基于该异质结的二极管的Ⅰ-Ⅴ电流曲线表现出显著的整流效应,计算的理想因子是1.3,证明扩散电流主导;在光激发下,该异质结表现出显著的光伏效应和3.5%的光电转化效率。发展了常压化学气相沉积法制备二维α-In₂Se₃薄膜的新方法。在氟金云母基底上成功制备出单晶尺寸100μm的、少层三角形状的单晶In₂Se₃薄膜。研究不同基底二维α-In₂Se₃薄膜的生长机理,通过改变氟金云母基底的表面形貌,成功制备出各种大面积的、图案化的二维In₂Se₃薄膜。开发了二维In₂Se₃薄膜的力学传感器并研究传感器对人体动作的监测性能。在不同的拉伸和压缩力作用下,二维In₂Se₃薄膜表现出显著的压阻效应和良好的稳定性。制备了二维In₂Se₃薄膜的力学传感器和传感器阵列,监测人体动作实验结果证实该传感器对人体活动具有高的灵敏度和良好的稳定性,传感器阵列表现出良好的空间分辨率。本论文的工作丰富了硒化铟薄膜的制备和光电性能研究,为其在高性能微电子器件、光电子器件和力学传感器件等相关领域的应用打下坚实的基础。更多还原

【Abstract】 Two-dimensional（2D）semiconductors are hot field of research in materials and microelectronics due to their unique physical and chemical properties,which are different from their bulk materials,making their huge potential application in nanoelectronic devices and nano-optoelectronic devices.However,stable and highperformance semiconductors are needed to be further explored.Indium selenide,including InSe and In₂Se₃,are typical IIⅠ-ⅤI group layered semiconductors.Bulk InSe and In₂Se₃ display good stability,high electron mobility and high light absorption coefficient,making great potential application in high performance electronic and optoelectronic devices.Up to now,research on 2D indium selenide still be limited and lots of properties should be further investigated.Herein,synthesis methods of 2D indium selenide are investigated and the field effect transistors（FETs）and phototransistor based on InSe are fabricated.The transport and photodetection properties of multilayer InSe are explored.The InSe-CuInSe₂ lateral heterojunctions are fabricated and its electronic and photovoltaic performance are investigated.The strain sensors and e-skin devices based on 2D In₂Se₃ are fabricated,and their performance of monitoring human activity are systematically investigated.2D β-InSe nanoflakes on various substrates are fabricated by mechanical exfoliation method.The relationship between Raman/PL spectrums and InSe thickness are explored.The multilayer InSe field-effect-transistors（FETs）are fabricated and the electronic transport properties are investigated.The performance of multilayer InSe FETs is comparable to monocrystalline silicon electronic devices.The electronic transport performances of InSe FETs with various electrodes（Al,Ti,In and Cr）are consistent with the surface roughness of electrodes rather than metal work function.The results of experiment and theory simulation demonstrate that contact resistance between metal electrode and 2D InSe is determined by number of electron in d orbital.The metal Cr is good metal electrode for 2D InSe nanoflakes.The instability in InSe FETs is totally different between in air and vacuum conditions after applying gate-bias.These results demonstrate that gate-bias induced instability in InSe FETs is attributed to adsorption and desorption process of oxygen and/or water molecules on the InSe surface controlled by gate-bias.The electronic transport performance of InSe FETs with various dielectric materials is investigated.The PMMA/oxide double layer dielectrics can significantly improve the electronic transport performance of InSe FETs.The results of surface roughness and contact angle measurement indicate that coulomb impurities scattering（CIs）and surface polar phonon scattering（SPP）from oxidized dielectric can be effectively suppressed by PMMA layer.The model of multiple reflection-adsorption process of the light adsorption in multilayer InSe is established.The theoretical simulation demonstrates that the light adsorption in InSe is nonlinearly depended on thickness of InSe.Multilayer InSe phototransistors are fabricated and the photodetection performance is investigated.Multilayer InSe phototransistor shows broad photodetection range under various illumination wavelengths and intensities.The ultrahigh photoresponse is confirmed by calculated responsivity and detectivity.Flexible InSe photodetector shows a good stability under multi-cycle bending.A new method for the fabrication of InSe-CuInSe₂ lateral p-n heterojunction by solid-state-reaction is developed.The electronic and photovoltaic performance of InSe-CuInSe₂ lateral p-n heterojunction are investigated.The Ⅰ-Ⅴ curve of diode based on InSe-CuInSe₂ lateral p-n heterojunction displays significant rectification effect.The calculated ideality factor is 1.3 and demonstates that the rectification current is dominated by diffusion current.This heterojunction also possesses significant photovoltaic effect and light-power conversion efficiency of 3.5% under light illumination.A new method for the synthesis of 2D α-In₂Se₃ thin films by atmospheric pressure chemical vapor deposition is developed.The lateral size of few layer In₂Se₃ thin films is 100 μm on mica.The growth mechanisms of 2D α-In₂Se₃ on different substrates are explored.Various large-scale and patterned In₂Se₃ thin-films are successfully fabricated by tuning surface morphology of mica.The strain sensor and sensor arrays based on 2D In₂Se₃ thin-film are developed and its application to monitor human actions is explored.2D In₂Se₃ thin-film shows significant piezoresistive effect and good stability under various tensile and compression stress.The flexible and wearable strain sensor and sensor arrays based 2D In₂Se₃ thin-film are fabricated and performance of monitoring human activities is investigated.The results clarify that 2D In₂Se₃ strain sensor shows high sensitivity and good stability for human activities,and sensor arrays show good spatial resolution on conformal surfaces.This thesis has enriched the synthesis methods and electronic and optoelectronic properties of InSe/In₂Se₃ nanoflakes,paving a way for InSe/In₂Se₃ application in high performance electronic devices,optoelectronic devices and strain sensors.更多还原