实现不同基底间高效率、高质量的二维原子晶体转移(即转移技术),是开展二维晶体异质结及柔性器件研究与应用的关键.近年以二硫化钼为代表的过渡金属硫化物(transition metal dichalcogenides,TMDs)二维半导体已成为继石墨烯之后的二维...实现不同基底间高效率、高质量的二维原子晶体转移(即转移技术),是开展二维晶体异质结及柔性器件研究与应用的关键.近年以二硫化钼为代表的过渡金属硫化物(transition metal dichalcogenides,TMDs)二维半导体已成为继石墨烯之后的二维材料研究热点.目前,TMDs常用转移技术主要包括湿法转移、干法转移、热释放胶带辅助、表面能辅助、鼓泡转移以及真空热压法等.这些方法各有利弊:湿法转移成本低、步骤简洁,但依赖聚合物支撑,容易对TMDs造成污染;干法转移借助精密位移技术可实现精准控制,特别适用微晶定位转移,但转移成功率有待提升;热释放胶带巧妙利用金属膜与TMDs二维材料间较强的吸附力,能够在不转移的情况下,直接在原始基底上构造阵列结构,但步骤相对复杂;表面能辅助法利用水在不同界面表面能差异,可实现快速自动剥离,但易引入褶皱;鼓泡转移则是通过电化学或超声方式产生的气泡崩塌使二维材料与基底界面分离,同样材料表面容易产生褶皱和破裂等缺陷;真空热压法在组装高质量、大面积多层异质结方面独具优势.该述评可为恰当选择转移方法提供指引.展开更多
Passive harmonic mode locking of an erbium-doped fiber laser based on few-layer molybdenum disulfide(MoS2)saturable absorber(SA) is demonstrated. The few-layer MoS2 is prepared by the chemical vapor deposition(CVD) me...Passive harmonic mode locking of an erbium-doped fiber laser based on few-layer molybdenum disulfide(MoS2)saturable absorber(SA) is demonstrated. The few-layer MoS2 is prepared by the chemical vapor deposition(CVD) method and then transferred onto the end face of a fiber connector to form a fiber-compatible Mo S2SA. The 20 th harmonic modelocked pulses at 216-MHz repetition rate are stably generated with a pulse duration of 1.42 ps and side-mode suppression ratio(SMSR) of 36.1dB. The results confirm that few-layer MoS2 can serve as an effective SA for mode-locked fiber lasers.展开更多
Initiated by graphene, two-dimensional(2D) layered materials have attracted much attention owing to their novel layer-number-dependent physical and chemical properties. To fully utilize those properties, a fast and ac...Initiated by graphene, two-dimensional(2D) layered materials have attracted much attention owing to their novel layer-number-dependent physical and chemical properties. To fully utilize those properties, a fast and accurate determination of their layer number is the priority. Compared with conventional structural characterization tools, including atomic force microscopy, scanning electron microscopy, and transmission electron microscopy, the optical characterization methods such as optical contrast, Raman spectroscopy, photoluminescence, multiphoton imaging, and hyperspectral imaging have the distinctive advantages of a high-throughput and nondestructive examination. Here, taking the most studied 2D materials like graphene, MoS_2, and black phosphorus as examples, we summarize the principles and applications of those optical characterization methods. The comparison of those methods may help us to select proper ones in a cost-effective way.展开更多
文摘实现不同基底间高效率、高质量的二维原子晶体转移(即转移技术),是开展二维晶体异质结及柔性器件研究与应用的关键.近年以二硫化钼为代表的过渡金属硫化物(transition metal dichalcogenides,TMDs)二维半导体已成为继石墨烯之后的二维材料研究热点.目前,TMDs常用转移技术主要包括湿法转移、干法转移、热释放胶带辅助、表面能辅助、鼓泡转移以及真空热压法等.这些方法各有利弊:湿法转移成本低、步骤简洁,但依赖聚合物支撑,容易对TMDs造成污染;干法转移借助精密位移技术可实现精准控制,特别适用微晶定位转移,但转移成功率有待提升;热释放胶带巧妙利用金属膜与TMDs二维材料间较强的吸附力,能够在不转移的情况下,直接在原始基底上构造阵列结构,但步骤相对复杂;表面能辅助法利用水在不同界面表面能差异,可实现快速自动剥离,但易引入褶皱;鼓泡转移则是通过电化学或超声方式产生的气泡崩塌使二维材料与基底界面分离,同样材料表面容易产生褶皱和破裂等缺陷;真空热压法在组装高质量、大面积多层异质结方面独具优势.该述评可为恰当选择转移方法提供指引.
基金supported by the National Natural Science Foundation of China(Grant Nos.61378028,61421002,61475030,and 61377042)the National Basic Research Program of China(Grant No.2012CB315701)the New Century Excellent Talents Program in University,China(Grant No.NCET-13-0092)
文摘Passive harmonic mode locking of an erbium-doped fiber laser based on few-layer molybdenum disulfide(MoS2)saturable absorber(SA) is demonstrated. The few-layer MoS2 is prepared by the chemical vapor deposition(CVD) method and then transferred onto the end face of a fiber connector to form a fiber-compatible Mo S2SA. The 20 th harmonic modelocked pulses at 216-MHz repetition rate are stably generated with a pulse duration of 1.42 ps and side-mode suppression ratio(SMSR) of 36.1dB. The results confirm that few-layer MoS2 can serve as an effective SA for mode-locked fiber lasers.
基金supported by the foundation for Innovation Research Groups of the National Natural Science Foundation of China(NSFC)(Grant No.61421002)the National Natural Science Foundation of China(Grant Nos.61475030,615224030,and 61605024)the Central University Basic Scientific Research Business Expenses(Grant No.ZYGX2015Z001)
文摘Initiated by graphene, two-dimensional(2D) layered materials have attracted much attention owing to their novel layer-number-dependent physical and chemical properties. To fully utilize those properties, a fast and accurate determination of their layer number is the priority. Compared with conventional structural characterization tools, including atomic force microscopy, scanning electron microscopy, and transmission electron microscopy, the optical characterization methods such as optical contrast, Raman spectroscopy, photoluminescence, multiphoton imaging, and hyperspectral imaging have the distinctive advantages of a high-throughput and nondestructive examination. Here, taking the most studied 2D materials like graphene, MoS_2, and black phosphorus as examples, we summarize the principles and applications of those optical characterization methods. The comparison of those methods may help us to select proper ones in a cost-effective way.
