摘要
提出了一种实现高性能宽带近红外热电子光电探测器的多层薄膜器件结构,该结构基于TiN/TiO_(2)肖特基势垒和TiN/分布式布拉格反射器形成的塔姆等离激元。通过光学传输矩阵和热电子发射理论模拟计算结果表明,高折射率比介质层构成的分布式布拉格反射器有效扩展了TiN薄膜吸收光谱和器件响应光谱,同时增强了TiN薄膜的吸收率和器件响应度。通过调控分布式布拉格反射器结构参数、TiN薄膜厚度和MgF减反射层厚度,可获得高达29.2 mA/W的响应度,响应光谱半峰全宽约为900 nm,为高性能宽带近红外热电子器件的实现提供了新的途径,有利于拓展热电子光电探测器的应用领域。
Photodetection is an important means of modern detection and intelligent sensing technology.Classical photodetectors are based on the interband transition of electrons in the semiconductor materials,and their maximum response wavelength depends on the optical band gap of the semiconductor materials.Only photons with energy higher than the band gap(wavelength less than the maximum response wavelength)can be detected. Infrared photoelectric detectors are widely used in military reconnaissance,aerospace remote sensing,astronomical observation,industrial detection,optical fiber communication,infrared imaging and other fields. Common infrared detectors are made of semiconductor materials with extremely narrow band gap,which are facing many problems such as complex processes,high costs and low operation temperature. Hot electrons photodetectors based on the internal photoelectric effect have attracted tremendous attention in the past decade due to its advantages such as overcoming the response limitation of the semiconductor band gap,fast response speed,working at room temperature and light polarization sensitivity. The main problem of hot electrons photodetectors is low device responsivity,especially in the near infrared regions. In recent years,numerous studies at home and abroad have demonstrated that optical means such as grating plasmons,Tamm plasmons and micro-cavity effect can effectively enhance the optical absorption of metal films in the hot electrons photodetectors,and further improve the device responsivity. The planar metal thin films/Distributed Bragg Reflector(DBR)Tamm plasmons have many advantages such as simple structure,low manufacturing cost,high absorption efficiency. By changing the DBR structure parameters and metal thin films thickness,the resonance wavelength and maximum response wavelength can be adjusted. This structure provides an effective way to improve the absorption of hot electrons photodetectors,but the corresponding devices normally exhibits narrowband absorption and responsivity. The development of hot electrons photodetectors with broadband response characteristics is conducive to the expansion of its applications in optical fiber communication,photocatalysis,solar cells,solar water splitting and other fields. In view of broadband hot electrons photodetector,there are still some issues to be solved,such as narrow response spectra,low absorption efficiency,and low responsivity. TiN has high dielectric constants and excellent plasmons characteristics in the near infrared ranges. Moreover,the mean free path of hot electrons in the TiN thin films is about 50nm,which is larger than the values of Au and Ag. Therefore,TiN is considered as potential candidate which can be used to achieve high performance broadband hot electrons photodetectors. In this study,we propose a multi-layer device architecture based on the TiN/TiO_(2) Schottky barrier and the Tamm plasmons formed by the TiN/DBR structure to achieve high-performance broadband near infrared hot electrons photodetectors. This architecture has the following characteristics:1) The TiN/DBR Tamm plasmons with manipulating the DBR structural parameters are able to enhance broadband absorption of the TiN thin films and broaden the device response spectra;2)The Schottky barrier of TiN/TiO_(2) is only 0.37 eV,which will be beneficial to the transporting of low energy hot electrons;3)The MgF anti-reflectance layer is used to reduce optical loss. Based on the optical transfer matrix and hot electrons emission theory,we firstly simulated the reflection and absorption spectra of the hot electrons photodetectors. Furthermore,we calculated the corresponding device responsivity. The simulation results show that with high refractive indices ratio dielectric layers,the DBR form by Ge/SiO_(2) can effectively expand the absorption spectra of the TiN thin films and the device response spectra. The absorption of TiN thin films and device responsivity also can be largely enhanced. By adjusting the DBR structural parameters,such as dielectric layers,DBR period and the DBR center wavelength,the absorption spectra of TiN thin films and the responsivity spectra of the hot electrons devices can be regulated. We also discuss the influences of the thickness of TiN thin films and MgF anti-reflectance layer. The maximum absorption of the TiN thin films is 99.8%,and the maximum responsivity value of the optimized device is 29.2 mA/W. The full width at half maximum of the response spectra is about 900 nm. The simulation results indicate that as the incident angle increases from 0 to 30°,the Tamm state can still be excited,but the peak absorption of the TiN thin films and the device responsivity are decreased. The peak absorption and response wavelength under the TE polarization and TM polarization are both blue shifted with the increasing of incident angles. This multilayer device architecture provides a new route to realize high-performance broadband near infrared hot electrons devices. Meanwhile,it is beneficial to expand the applications of hot electrons photodetectors.
作者
罗国平
陈星源
胡素梅
朱伟玲
LUO Guoping;CHEN Xingyuan;HU Sumei;ZHU Weiling(School of Science,Guangdong University of Petrochemical Technology,Maoming,Guangdong 525000,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2022年第4期150-160,共11页
Acta Photonica Sinica
基金
国家自然科学基金(No.12074441)
广东省科技计划(Nos.2018A03030728,2019A1515010916)
广东省教育厅青年创新人才项目(No.2017KQNCX136)
广东石油化工学院科研基金(No.2017rc20)。
关键词
光电探测器
热电子
等离激元
量子效率
薄膜
Photodetectors
Hot electrons
Plasmons
Quantum efficiency
Thin films
