Enhancement of ultraviolet light responsivity of a pentacene phototransistor by introducing photoactive molecules into a gate dielectric
Enhancement of ultraviolet light responsivity of a pentacene phototransistor by introducing photoactive molecules into a gate dielectric
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DOI：
10.7567/jjap.53.02bb03
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发表时间：
2014-01
影响因子：
1.5
通讯作者：
T. T. Dao-T.;T. Matsushima;M. Murakami;K. Ohkubo;S. Fukuzumi;H. Murata
中科院分区：
文献类型：
--
作者：
T. T. Dao-T.;T. Matsushima;M. Murakami;K. Ohkubo;S. Fukuzumi;H. Murata
提出了一种制备并五苯晶体管结构紫外光探测器的新方法，将光敏分子6-[4′-（N，N-二苯基氨基）苯基]-3-乙氧羰基香豆素（DPA-CM）引入到聚甲基丙烯酸甲酯（PMMA）栅介质中。DPA-CM分子强烈吸收紫外光并形成稳定的电荷分离态。当负栅极电压扫描到晶体管的栅极电极时，DPA-CM分子的电荷分离态被转换为自由电子和空穴。自由电子穿过并随后到达PMMA：DPA-CM层和聚苯乙烯缓冲层的界面，诱导并五苯通道中额外空穴的积累。因此，在2.54mW/cm ~ 2的365 nm紫外光照射下，晶体管的漏电流显著增加了6.1 × 102倍。此外，光电晶体管表现出0.12A/W的高光响应度，这比常规并五苯光电晶体管的光响应度大约一个数量级[Lucas等人，Thin Solid Films 517，280（2009）]。这一结果将有助于高性能紫外光探测器的制造。
We demonstrated a new approach to fabricate an ultraviolet (UV) photodetector with a pentacene transistor structure where photoactive molecules of 6-[4′-(N,N-diphenylamino)phenyl]-3-ethoxycarbonylcoumarin (DPA-CM) were introduced into a poly(methyl methacrylate) (PMMA) gate dielectric. DPA-CM molecules strongly absorb UV light and form stable charge-separation states. When a negative gate voltage was scanned to a gate electrode of the transistor, the charge-separation states of DPA-CM molecules were converted into free electrons and holes. The free electrons traversed and subsequently reached an interface of the PMMA:DPA-CM layer and a polystyrene buffer layer, inducing accumulation of additional holes in a pentacene channel. Therefore, under 2.54 mW/cm2 of 365 nm UV irradiation, a marked increase in drain current by 6.1 × 102 times were obtained from the transistor. Moreover, the phototransistor exhibited a high light responsivity of 0.12 A/W which is about one order of magnitude larger than that of a conventional pentacene phototransistor [Lucas et al., Thin Solid Films 517, 280 (2009)]. This result will be useful for manufacturing of a high-performance UV photodetector.