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中国物理学会期刊

高压下HfS2的光电性质

CSTR: 32037.14.aps.74.20250893

Photoelectric properties of HfS2 under high pressure

CSTR: 32037.14.aps.74.20250893
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  • HfS2作为一种典型的IVB族过渡金属硫化物(transition metal dichalcogenides, TMDs)材料, 凭借其高载流子迁移率和层间电流密度特性, 在光传感、通信、成像等多个前沿领域展现出巨大的潜在应用价值. 近年来的研究揭示了压力对TMDs光谱响应范围和电输运性质的重要调控作用, 这激发了我们对HfS2光电性质进行压力调控的研究兴趣. 本研究采用金刚石对顶砧装置进行高压原位光电流、拉曼散射光谱、交流阻抗谱和紫外-可见吸收光谱测量, 并结合第一性原理计算, 系统探究了压力对 HfS2 电输运和光电性质的影响. 研究结果显示, HfS2 的光电流随着压力的增加持续增强. 30.1 GPa时, HfS2的光电流比初始值提高了5个数量级, 这一显著增强归因于S-S层间作用力增强导致的带隙和电阻减小. 此外, 光学测量实验及理论计算结果进一步表明, HfS2的晶体结构、禁带宽度及光学性质均可通过压力进行有效调控. 本研究为压力调控层状材料的光电性能提供了新思路.

     

    HfS2, as a typical IVB group transition metal dichalcogenide (TMD) material, has shown great potential applications in various fields such as photo-sensing, communication, and imaging due to its high carrier mobility and interlayer current density characteristics. Recent studies have revealed the significant role of pressure in modulating the spectral response range and electrical transport properties of TMDs, which has aroused our interest in studying the pressure regulation of the optoelectronic properties of HfS2. In this study, diamond anvil cell based high-pressure in-situ photocurrent, Raman scattering spectroscopy, alternating current impedance spectroscopy, ultraviolet-visible absorption spectroscopy measurements, and combined first-principles calculations are used to systematically investigate the effects of pressure on the electrical transport and optoelectronic properties of HfS2. The experimental results show that the photocurrent of HfS2 continuously increases with pressure rising. Within a pressure range of 0–10.2 GPa, the photocurrent and response of HfS2 show a rapid upward trend with pressure rising; at 10.2 GPa, the photocurrent and response of HfS2 (Iph = 0.32 μA, R = 8.19 μA/W) are about three orders of magnitude higher than their initial values at 0.5 GPa (Iph = 1.40 × 10–4 μA, R = 3.56 × 10–3 μA/W). At the pressure above 10.2 GPa, the growth rate of photocurrent and response slow down significantly, which are related to the structural phase transition of HfS2 near 10.0 GPa. Further compression to 30.1 GPa results in a maximum photocurrent of 3.35 μA, which is five orders of magnitude higher than its initial value at 0.5 GPa. This significant enhancement is attributed to the strengthening of S-S interlayer interaction forces under pressure, which leads band gap and resistivity to decrease. In addition, based on the modified Becke-Johnson (mBJ) exchange-correlation potential, the electronic band structure and optical properties of HfS2 in its initial phase are calculated and analyzed using WIEN2K software package. The calculation results show that with the increase of pressure, the optical absorption coefficient and the real part of the photoconductivity of HfS2 along the c-axis significantly increase, which further reveals the intrinsic physical mechanism of the enhanced photoresponse of HfS2 under pressure. This study offers a new insight into pressure regulated optoelectronic properties of layered materials.

     

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