基於維度侷限結構之二維輻射熱計

Abstract

近年來，科學家們致力於紅外成像領域的發展;其中，對輻射熱能具有高靈敏度的感測器──輻射熱計，受到了高度重視。輻射熱計藉由吸收輻射熱能後迅速改變的電阻作為感測機制，因此電阻溫度係數(temperature coefficient of resistance，TCR)是用以定義輻射熱計性能的重要參數。本作中，我們將剪切剝離的二維材料沈積於聚二甲基矽氧烷(PDMS)以形成被結構侷限於特定維度的薄膜;我們演示了以不同維度排列的石墨烯薄膜的輻射熱計表現，並利用二硫化鉬(MoS2)實現一種具有出色靈敏度及解析度的透明、低成本輻射熱計，其電阻溫度係數達到 133 %K-1 且其歸一化電流響應率(normalized current responsivity)高達-7.7 × 105 %W-1。此外，我們也將類似結構應用於石墨烯與二硫化鉬的組合，並演示了兩種光偵測器:石墨烯接觸型二硫化鉬光偵測器以及二硫化鉬參雜型石墨稀光偵測器。本作中的結果不僅顯示了局限於聚合物結構中二維薄膜的低成本及高靈敏度的特性，更暗示了二維薄膜在不同維度下的光電應用潛力。

Bolometer, a device for infrared (IR) thermal imaging, has been developed a lot in recent years. Electrical resistance of a bolometer varies rapidly due to the change in temperature caused by the absorption of IR radiation, so the temperature coefficient of resistance (TCR) is a vital parameter for characterizing the performances of bolometers. Here, based on the thin film of shear exfoliated two-dimensional (2D) materials confined in the polydimethylsiloxane (PDMS) substrate, we demonstrate the bolometric performances of the graphene films in different dimensions, and report a low-cost, transparent molybdenum disulfide (MoS2) bolometer with outstanding sensitivity, whose normalized current responsivity is up to -7.7 × 105 %W-1 and TCR achieves 133 %K-1. Its extremely tiny active area as pixel length facilitates high spatial resolution thermal imaging. In addition, we produce a graphene-contact MoS2 photodetector and a MoS2- doped graphene photodetector in the similar structure. These results not only present the properties of the low cost and high transparency of the 2D material films confined in the polymer structure but also imply the optoelectronics applications of thin films arranged in another dimension.