n-硒化铟/p-黑磷范德瓦尔斯异质结光探测器的性能调控和机理探究

Van der Waals p-n heterojunctions have been widely used in optoelectronic devices due to their excellent properties. However, the material bandgap, low carrier mobility and the limitation of p-type materials are important factors that restrict the further improvement of the performance of two-dimensional p-n heterojunction photodetectors. Two-dimensional n-type indium selenide combined with p-type black phosphorus can form Ⅱ type heterojunctions with suitable band gap and high optical absorption coefficient and carrier mobility, which has a series of advantages over other heterostructures of the same type. In this project, we will fabricate novel wide spectrum ranging from the visible to near infrared bands, low noise, fast response photodetectors based on this heterojunction and explore their photoelectric properties. By discussing the intrinsic physical mechanism of the effects of different fabrication processes on the mass and I-V characteristics of heterojunction and calculating the band structure and charge transfer according to the first principles, we will on one hand investigate the regulation mechanisms of exciting light, applied voltage and material thickness on the spectral response time, detection wavelength range, noise and photoresponsivity of the detector, and on the other hand reveal the mechanisms of photoinduced carrier transition and transport in the heterojunction. The implementation of this project will provide significant guidance for the design, fabrication and performance exploration of van der Waals heterojunction devices.

范德瓦尔斯p-n异质结因其优异性能在光电器件中具有潜在广泛应用。但材料带隙、低载流子迁移率和p型材料的局限成为目前制约p-n异质结光探测器性能进一步提高的重要因素。二维n型硒化铟和p型黑磷结合可形成合适带隙组合的Ⅱ类异质结，并且具有高的光吸收系数和载流子迁移率，相比其它同类型异质结具有一系列优势。本项目拟基于该异质结制备覆盖可见光到近红外波段的新型宽光谱、低噪声、快响应光探测器并对其光电性能展开深入探究。通过探讨不同异质结制备工艺对异质结质量和I-V特性影响的内在物理机制，制备高质量异质结器件，结合第一性原理计算的能带结构、电荷转移等，一方面探索激发光、外加电压和材料厚度等对探测器光谱响应时间、探测波长范围、噪声和光响应度等参数的调控机制，另一方面揭示光照下异质结中光生载流子的跃迁、输运等光电转换机制。本项目实施将为范德瓦尔斯p-n异质结器件的设计制备、性能探究等提供重要指导。

范德瓦尔斯p-n异质结因其优异性能在光电器件中具有潜在广泛应用。但材料带隙、载流子迁移率和p型材料的选择成为目前制约二维p-n异质结光探测器性能进一步提高的关键。本项目将具有高的光吸收系数和载流子迁移率以及合适带隙组合的n型硒化铟(InSe)和p型黑磷（Black Phosphorus-BP）结合形成具有Ⅱ型能带结构的异质结，成功制备了新型范德瓦耳斯InSe/BP异质结光电探测器并对其光电性能展开探究。该探测器响应光谱范围覆盖紫外到近红外波段(300nm-1000nm)；该器件在300nm波长光照下响应度可达50A/W以上，在638nm和980nm波长光照下响应度也分别达到约7.0A/W和2.5A/W，达到同类型器件的中上水平；探测器的噪声等效功率NEP最低值可达10^-15W/Hz^1/2量级, 探测灵敏度D*最高达10^12Jones；在300nm、638nm和980nm光照下的开/关时间分别为0.15/2.88ms，0.26/0.50ms和0.23/0.74ms。本项目实施将深化对二维硒化铟和黑磷结构、性质的认识，同时探测器制备为相关二维材料的实际应用打下了坚实的基础。