Effects of titanium and niobium nanosheets on the performance of selenium gigahertz/terahertz electro-optical filters

IF 4 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Optical and Quantum Electronics Pub Date : 2025-05-12 DOI:10.1007/s11082-025-08223-y

A. F. Qasrawi, Weam A. M. Tahayna

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Abstract

Selenium thin films coated onto glass and Pt substrates are designed as electro-optical filters suitable for utilization in the gigahertz and terahertz frequency domains. Depositing titanium and niobium nanosheets onto the Se films enhanced their structural, optical, dielectric, and electrical properties. Specifically, Ti and Nb nanosheets improve the crystallinity, suppressed free carrier absorption, narrowed the energy band gap of Se from 1.86 eV to 1.55 eV and 1.25 eV, respectively, and widened the tail states from 0.29 eV to 0.60 eV and 0.78 eV, respectively. Furthermore, as a dielectric layer, Nb nanosheets decreased the dielectric constant more effectively than Ti nanosheets. This reduction resulted in a remarkable enhancement in the terahertz cutoff frequency by 267% and 620% at an incident photon energy of 1.85 eV. Electrical measurements conducted in the frequency range of 0.01–1.50 GHz revealed wide tunability of capacitance and microwave cutoff frequency based on the imposed carrier frequency. Additionally, analyses aimed at determining the electro-optical parameters of the gigahertz/terahertz filters indicated free charge carrier concentrations in the range of 10¹⁷–10¹⁹ cm⁻³ and drift mobility values of 4.07–13.56 cm²/Vs, associated with the propagation of light signals in the infrared and visible light frequency domains. The enhanced properties of Se/(Ti, Nb) band filters show promise for a variety of electro-optical applications, including terahertz and 4G technologies.

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钛和铌纳米片对硒千兆赫/太赫兹光电滤光片性能的影响

硒薄膜涂覆在玻璃和铂基板上，设计成适合在千兆赫和太赫兹频率域使用的电光滤光片。在Se薄膜上沉积钛和铌纳米片，增强了Se薄膜的结构、光学、介电和电学性能。具体来说，Ti和Nb纳米片提高了结晶度，抑制了自由载流子的吸收，将Se的能带隙分别从1.86 eV缩小到1.55 eV和1.25 eV，将尾态分别从0.29 eV扩大到0.60 eV和0.78 eV。此外，作为介电层，铌纳米片比钛纳米片更有效地降低了介电常数。当入射光子能量为1.85 eV时，这一减小导致太赫兹截止频率显著提高267%和620%。在0.01-1.50 GHz频率范围内进行的电测量表明，电容和微波截止频率基于所施加的载波频率具有广泛的可调性。此外，对千兆赫/太赫兹滤波器的电光参数的分析表明，自由载流子浓度在1017-1019 cm−3范围内，漂移迁移率值为4.07-13.56 cm2/Vs，与光信号在红外和可见光频率域的传播有关。Se/(Ti, Nb)频带滤波器的增强特性显示了各种电光应用的前景，包括太赫兹和4G技术。

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来源期刊

Optical and Quantum Electronics 工程技术-工程：电子与电气

CiteScore

4.60

自引率

20.00%

发文量

810

审稿时长

3.8 months

期刊介绍： Optical and Quantum Electronics provides an international forum for the publication of original research papers, tutorial reviews and letters in such fields as optical physics, optical engineering and optoelectronics. Special issues are published on topics of current interest. Optical and Quantum Electronics is published monthly. It is concerned with the technology and physics of optical systems, components and devices, i.e., with topics such as: optical fibres; semiconductor lasers and LEDs; light detection and imaging devices; nanophotonics; photonic integration and optoelectronic integrated circuits; silicon photonics; displays; optical communications from devices to systems; materials for photonics (e.g. semiconductors, glasses, graphene); the physics and simulation of optical devices and systems; nanotechnologies in photonics (including engineered nano-structures such as photonic crystals, sub-wavelength photonic structures, metamaterials, and plasmonics); advanced quantum and optoelectronic applications (e.g. quantum computing, memory and communications, quantum sensing and quantum dots); photonic sensors and bio-sensors; Terahertz phenomena; non-linear optics and ultrafast phenomena; green photonics.