以鹽輔助常壓化學氣相沉積(APCVD)的方法合成少層數多過渡金屬硫系合金晶體，並確認此合金晶體為少層數成分濃度梯度MoWSSe合金晶體。使用微影蝕刻的方式，透過將兩個電極連接至MoWSSe合金晶體的不同成分濃度位置來製作異質接面光感測器元件，並進行性能量測。在從紫外光到紅外光的各種光波長的照射下，此光感測器元件在可見光範圍內表現出最高性能：大於10 A/W的響應度，大於5×10^10 jones的偵測度，以及大於3000%的外部量子效率；在近紅外光波段也仍舊有大於1 A/W的響應度，大於5×10^9 jones的偵測度，以及大於150%的外部量子效率；且有小於5毫秒的快速上升時間。此光感測器元件的卓越性能是由於有多個p-n異質接面在少層數成分濃度梯度MoWSSe合金晶體中產生，並形成助於光生電子-電洞對的分離的內置電場。將MoWSSe合金晶體異質接面光感測器元件進行退火處理，結晶度的提升能改善開關比、偵測度和響應速度。

A few-layered multi-transition metal dichalcogenide alloy crystal was synthesized using salt-assisted atmospheric pressure chemical vapor deposition (APCVD) and confirmed to be a composition-gradient MoWSSe alloy crystal. A heterojunction photodetector device was fabricated by connecting two electrodes to different composition gradient regions of the MoWSSe alloy crystal using lithography and etching methods. Performance measurements were conducted, showing the photodetector device exhibited the highest performance under visible light, with a responsivity greater than 10 A/W, detectivity over 5×10^10 jones, and external quantum efficiency exceeding 3000%. Even in the near-infrared wavelength range, the device still showed a responsivity greater than 1 A/W, detectivity over 5×10^9 jones, and external quantum efficiency over 150%. The rise time was also less than 5 milliseconds. The outstanding performance of this photodetector device is attributed to the multiple p-n heterojunctions formed within a few-layered composition-gradient MoWSSe alloy crystal, generating an internal electric field that facilitates the separation of photo-generated electron-hole pairs. Post-annealing treatment of the MoWSSe alloy heterojunction photodetector device enhanced its crystallinity, improving the on-off ratio, detectivity, and response speed.

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