关键词: MoS2, 光电探测器, 高温, 六方氮化硼

Abstract: MoS₂ possesses numerous excellent optoelectronic properties, such as outstanding light absorption capability, a wide photoresponse range, and high photoelectric conversion efficiency, so it is applied in various fields. The research results indicate that the high-temperature stability of thin-layer MoS₂ faces significant challenges. When the temperature exceeds 200 ℃, a large number of sulfur (S) vacancies will form inside the material. These defect sites are prone to adsorb oxygen molecules from the environment, thereby causing unexpected doping effects and leading to fluctuations in electrical properties. If the temperature rises further to above 300 ℃, the material will undergo an oxidation reaction, and its intrinsic electrical characteristics and photoelectric response performance will undergo irreversible drastic changes. High-quality MoS₂ photodetectors are fabricated by using an embedded electrode structure with low contact resistance and transferring MoS₂ material onto the embedded electrode via dry transfer method. The device is annealed at different temperatures, and the structural changes of the material are characterized by Raman and photoluminescence spectroscopy. The temperature dependence of the device is analyzed by output and transfer characteristic curves as well as photocurrent response curves. The results show that after annealing at 300 ℃, both the rise time and decay time of the device are significantly shortened. The rise time decreases from 3.76 s to 48 ms, and the decay time reduces from 283.2 s to 23 ms. To further investigate the underlying mechanism, the experiment uses hexagonal boron nitride (h-BN) to encapsulate the top of MoS₂ for verification. It is found that encapsulation can effectively inhibit the formation of sulfur vacancies at high temperatures and the influence of oxygen doping in the air on the device performance. This provides theoretical and experimental basis for in-depth understanding of the temperature dependence of MoS₂ and optimizing its high-temperature stability in optoelectronic devices.

Key words: MoS2, photodetector, high temperature, hexagonal boron nitride