Zhang Renyun, Hummelgård Magnus, Forsberg Viviane, Andersson Henrik, Engholm Magnus, Öhlund Thomas, Olsen Martin, Örtegren Jonas, Olin Håkan
Department of Natural Sciences, Mid Sweden University, Holmgatan 10, SE, 85170, Sundsvall, Sweden.
Department of Electronic Design, Mid Sweden University, Holmgatan 10, SE, 85170, Sundsvall, Sweden.
Sci Rep. 2018 Feb 19;8(1):3296. doi: 10.1038/s41598-018-21688-0.
MoS has been studied intensively during recent years as a semiconducting material in several fields, including optoelectronics, for applications such as solar cells and phototransistors. The photoresponse mechanisms of MoS have been discussed but are not fully understood, especially the phenomenon in which the photocurrent slowly increases. Here, we report on a study of the photoresponse flash-light-processed MoS films of different thicknesses and areas. The photoresponse of such films under different light intensities and bias voltages was measured, showing significant current changes with a quick response followed by a slow one upon exposure to pulsed light. Our in-depth study suggested that the slow response was due to the photothermal effect that heats the MoS; this hypothesis was supported by the resistivity change at different temperatures. The results obtained from MoS films with various thicknesses indicated that the minority-carrier diffusion length was 1.36 µm. This study explained the mechanism of the slow response of the MoS film and determined the effective thickness of MoS for a photoresponse to occur. The method used here for fabricating MoS films could be used for fabricating optoelectronic devices due to its simplicity.
近年来，二硫化钼（MoS）作为一种半导体材料在包括光电子学在内的多个领域得到了深入研究，可用于太阳能电池和光电晶体管等应用。二硫化钼的光响应机制已被讨论，但尚未完全理解，尤其是光电流缓慢增加的现象。在此，我们报告了对不同厚度和面积的经闪光处理的二硫化钼薄膜的光响应研究。测量了此类薄膜在不同光强和偏置电压下的光响应，结果表明，在暴露于脉冲光时，电流发生显著变化，先是快速响应，随后是缓慢响应。我们的深入研究表明，缓慢响应是由于加热二硫化钼的光热效应所致；这一假设得到了不同温度下电阻率变化的支持。从不同厚度的二硫化钼薄膜获得的结果表明，少数载流子扩散长度为1.36微米。本研究解释了二硫化钼薄膜缓慢响应的机制，并确定了发生光响应的二硫化钼的有效厚度。这里用于制备二硫化钼薄膜的方法因其简单性可用于制造光电器件。
