本論文探討以化學氣相傳導法成長之二硫化鉬(MoS2)及硒化銦(InSe)層狀半導體之高頻時間解析光電導特性。實驗發現二硫化鉬及硒化銦皆存在包含快速及慢速的兩段式光電流響應。為了取得那段快速光電流響應的反應時間（載子活期）(τ1)，本研究架設了一套高頻時間解析光電導系統以進行量測。結果顯示二硫化鉬及硒化銦的載子活期最短可分別達到5 μs與10 μs，相對於第二段慢速光電流反應的載子活期(τ2)(>1 s）低了超過五個數量級。進行頻率相依之光電導量測時，發現其載子活期τ_1幾乎不隨雷射光照射頻率的改變而有差異。與其他材料比較起來， τ1皆優於其他層狀半導體ReS2, WS2與MoTe2。在環境相依光電導量測中，發現τ2會受到環境的影響，應是由表面主導的氧敏化光電導機制所造成。然而τ1幾乎不會受到環境的影響，推測是由材料內部的電洞陷阱（hole trap）所造成。在溫度相依之光電導量測，我們發現隨著溫度降低，τ1會隨之變長。藉由定量分析，可得到二硫化鉬和硒化銦的電洞陷阱之活化能約為1.9 meV和4.6 meV。

The high-frequency time-resolved photoconduction properties in molybdenum disulfide (MoS2) and indium selenide (InSe) single crystals grown by chemical vapor transport (CVT) have been investigated. We observe that both MoS2 and InSe exhibited the two-stage photocurrent response including a rapid response and a slow response. To investigate the rapid response time (i.e. carrier lifetime) ( τ1), a high-frequency time-resolved photoconductivity measurement system has been set up. The result shows that the τ1 values of the rapid photoresponse for the MoS2 and InSe can reach 5 μs and 10 μs respectively, which are over five orders of magnitude lower than the second and slower response times (τ2)（>1 s）. The τ1 values are lower than many photoconductors based on layered semiconductors, such as ReS2, WS2 and MoTe2. In addition, τ_1 is independent on the light frequency and measurement ambience, which is different from the ambience-sensitive τ2 induced by the surface-dominant oxygen-sensitized photoconduction mechanism. It is inferred that τ1 values are determined by the hole trapping mechanism in the inner bulks. The temperature-dependent photoconductivity measurements indicate that activation energies of shallow-level hole traps are 1.9 meV for MoS2 and 4.6 meV for InSe layered crystals.

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