本實驗主要目的為研究層狀過渡金屬硫化物W(S1-xSex)2的基本特性,並將其製作為光感測元件. 利用化學氣相傳導法合成含不同比例之W(S1-xSex)2, 並分別以拉曼光譜儀、X光能量散佈光譜儀進行定性與半定量的分析,結果顯示W(S1-xSex)2可以有效地利用莫爾數比計算控制其比例。首先我們將W(S1-xSex)2製作成金屬-半導體-金屬光感測元件，並進行電性量測, 在電導率量測中可以得到摻雜後改變其電導率的主要因子為載子濃度, 之後進行雷射光波長為405、532、632.8及808 nm的光電流量測。不同波長雷射光的光子能量所造成的光電流與樣品的本身的吸光度和表面吸收的效率有關, 這使得長波長所照射後的光響應為最佳, 而不同摻雜比例之間的歸一化光響應度會因為載子遷移率, 載子活期和量子轉換效率有直接關係, 而從此實驗中可以得到主導歸一化光響應度的主要因素為載子活期. 最後利用在真空及大氣環境下的光電流做比較, 可以發現到氧敏化機制的存在, 由於利用W(S1-xSex)2所製作成的光感測器屬於塊材結構, 因此氧敏化機制所造成的影響不大.

In this thesis, we investigated the photoconductive characteristics of the transition metal dichalcogenide W(S1-xSex)¬2 which is synthesized by chemical vapor transport method with different proportion. The results of EDS showed that the composition of W(S1-xSex)2 can be tunable effectively by calculating the mole number ratio of the starting material. Under controlling the component of W(S1-xSex)2, in the Raman spectra, the peak (247 cm-1) and the intensity of WSe2 gradually declined and shifted to the two peaks (A1g and E12g) of WS2, which are located at 355 cm-1 and 419 cm-1, respectively. The results showed that the composition proportion of W(S1-xSex)¬2 can be tunable effectively by calculating the mole number ratio of the starting materials. From the conductivities measurement, the value of conductivities was guided by the carrier concentration, impurities scattering and alloy scattering. We also made the W(S1-xSex)¬2 into metal-semiconductor-metal photoconductive detectors and then processed the measurement of photocurrent under different wavelength of laser sources, which were 405, 532, 632.8 and 808 nm. Because of the higher surface recombination rate for the shorter wavelength, the higher wavelength presents better photoresponse. Although the proportion of x influenced the conductivity, mobility, quantum efficiency and carrier lifetime of W(S1-xSex)¬2, The photoresponse was guided by the carrier lifetime. At last, the environment-dependent photocurrent indicated the photoconductive detectors of W(S1-xSex)¬2 followed the oxygen-sensitized photoconduction mechanism, but the photocurrent was less affected by the oxygen-sensitized photoconduction mechanism.

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