Excellence in Research: Mechanisms of Hyperdoping Silicon with Nitrogen

卓越的研究：氮超掺杂硅的机理

• 批准号: 2101220
• 负责人: Abdennaceur Karoui
• 金额: $ 50万
• 依托单位: North Carolina Central University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2023-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2101220&HistoricalAwards=false
• 关键词: Excellence; Research; Mechanisms; Hyperdoping; Silicon; Excellence; Research; Mechanisms; Hyperdoping; Silicon

Non-Technical: The successful incorporation of high amount of nitrogen in silicon enables absorption of infra-red (IR) light, unabsorbed by pure silicon. The IR absorption of such modified silicon is tuned through the initial amount of incorporated N and subsequent heat treatments. The new material leads to a new generation of IR devices as well as enhancing the efficiency of widely used silicon solar cells. In addition, silicon absorbing IR enables easier integration of optical devices in microelectronics, high speed parallel microprocessors with optical interconnections, smart high resolution IR cameras, smart remote-control devices, and the detection of small amounts of IR light. These applications are important for the economy, national security, future appliances, and energy security and sustainability.This project offers research topics for graduate students in physics and materials science, as well as a strong research training for undergraduate students. The project will advance the understanding of the science underlying materials for next generation computers, consumer electronics, and many other applications, while it promotes teaching and training of underrepresented students. Furthermore, students will learn through this collaboration involving three major universities interested in improving silicon, as well as two national laboratories operating the most advanced materials characterization techniques that are appropriate for this research. Summer research activities will be offered to high school students and transfer students from neighboring two-year colleges. High school teachers and two-year college faculty will be included, to increase recruitment of underrepresented students in STEM programs.Technical: This project will develop new understanding of the materials science of hyperdoping silicon with nitrogen, as well as the physics of IR optical processes. Preliminary data suggests that N complexes in hyperdoped silicon create an Intermediate Band (IB) that enhances absorption from near infrared (NIR) to Mid-IR through two photon absorption. Intertwined physics and materials science issues are addressed to understand phase transitions coupled to transformation of the electronic band structure and the IB generation. The emphasis is on the energy levels induced by V_x N_y O_z complexes (V represents a Si vacancy) in the bandgap of oxygen-rich Czochralski and Float Zone silicon, and their conversion to an optically efficient band. The challenging questions consist in unravelling the: i) atomic configurations of dominant V-N complexes that generate deep level donor centers, ii) their thermodynamic stability during heat treatments for hyperdoping, iii) the mechanism that drives local phase transformations in N-hyperdoped Si, whether by the Mott transition, electron pairing, or the energy level delocalization proposed in this project, iv) the requisites (e.g., band filling, sub-bands, band valleys, and other conditions) for the IB to work, and v) the IB efficiency versus the V-N type and concentration. Large N-related complexes are modeled as nanodot arrays; the effects of array symmetry breaking on energy level mixing in such coupled systems, level delocalization, level anti-crossing, and tunneling between levels are investigated to clarify conditions at which they contribute in IB generation.The experimental data is correlated with multiscale computer modeling of N-related complexes and disordered nanodot arrays. Both continuum and atomistic calculations are used. Strain at the atomic scale is considered in the calculations since it is a determinant factor for energy levels and the IB. Quantum group behavior of electrons in nanodot arrays will shed light on the energy delocalization that leads to IB formation. IR absorption and photoluminescence of N-hyperdoped Si will indicate the efficiency of the sequential IR optical transitions via the IB.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术性：成功掺入硅中的大量氮可以吸收纯硅未吸收的红外（IR）光。这种修饰的硅的IR吸收通过掺入的N和随后的热处理进行调节。新材料导致新一代的IR设备，并提高了广泛使用的硅太阳能电池的效率。此外，吸收IR的硅可以更轻松地集成微电子设备，具有光学互连的高速平行微处理器，智能高分辨率IR摄像头，智能遥控器件以及少量IR光的检测。这些应用对经济，国家安全，未来的设备以及能源安全和可持续性很重要。该项目为物理学和材料科学研究生以及针对本科生的强大研究培训提供了研究主题。该项目将促进对下一代计算机，消费电子产品以及许多其他应用程序的科学材料的理解，同时促进了代表性不足的学生的教学和培训。此外，学生将通过这项合作学习，涉及三所对改善硅的主要大学，以及两个经营最先进材料特征技术的国家实验室，适合这项研究。夏季研究活动将提供给高中生，并从邻近的两年学院转移学生。将包括高中教师和两年的大学教师，以增加STEM计划中代表性不足的学生的招聘。初步数据表明，超静态硅中的n个复合物创建了一个中间带（IB），通过两种光子吸收增强了从近红外（NIR）到MID-IR的吸收。解决了相互交织的物理和材料科学问题，以了解相结合电子带结构和IB生成的相结合。重点放在V_X N_Y O_Z复合物引起的能级（V表示富含氧气的Czochralski和Float Zone silicon的带隙中的SI空位），以及它们转换为光学效率的频段。具有挑战性的问题包括：i）在热处理过程中产生深层供体中心的主要V-N复合物的原子构型，ii）其热力处理期间的热力学稳定性，iii）驱动纳入n-耐荷耐磨的SI中的本地相变的机制，无论是通过Mott Tressition the Electition，Election project ing Injectition，还是Elective project ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing ing（ IB起作用的带填充，子带，带谷和其他条件），v）IB效率与V-N类型和浓度相比。大型N相关复合物被建模为纳米阵列。研究了阵列对称性破裂对这种耦合系统中能级混合的影响，水平的定位，电平抗跨和隧穿的水平之间的影响，以阐明它们在IB生成中贡献的条件。实验数据与N与NANODOT阵列的NANODOT阵列的多尺度计算机建模相关。使用连续性和原子计算。在计算中考虑了原子量表的应变，因为它是能级和IB的决定因素。纳米阵列中电子的量子组行为将阐明导致IB形成的能量）。 N型近植物SI的IR吸收和光致发光将通过IB表明顺序IR光学转变的效率。该奖项反映了NSF的法定任务，并被认为值得通过基金会的知识分子优点和更广泛的影响标准通过评估来进行评估。