Highly Responsive Ultrathin GaS Nanosheet Photodetectors on Rigid and Flexible Substrates

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• 作者：PingAn Hu ; Lifeng Wang ; Mina Yoon ; Jia Zhang ; Wei Feng ; Xiaona Wang ; Zhenzhong Wen ; Juan Carlos Idrobo ; Yoshiyuki Miyamoto ; David B. Geohegan ; Kai Xiao
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：April 10, 2013
• 年：2013
• 卷：13
• 期：4
• 页码：1649-1654
• 全文大小：382K
• 年卷期：v.13,no.4(April 10, 2013)
• ISSN：1530-6992

文摘

The first GaS nanosheet-based photodetectors are demonstrated on both mechanically rigid and flexible substrates. Highly crystalline, exfoliated GaS nanosheets are promising for optoelectronics due to strong absorption in the UV鈥搗isible wavelength region. Photocurrent measurements of GaS nanosheet photodetectors made on SiO₂/Si substrates and flexible polyethylene terephthalate (PET) substrates exhibit a photoresponsivity at 254 nm up to 4.2 AW^鈥? and 19.2 AW^鈥?, respectively, which exceeds that of graphene, MoS₂, or other 2D material-based devices. Additionally, the linear dynamic range of the devices on SiO₂/Si and PET substrates are 97.7 dB and 78.73 dB, respectively. Both surpass that of currently exploited InGaAs photodetectors (66 dB). Theoretical modeling of the electronic structures indicates that the reduction of the effective mass at the valence band maximum (VBM) with decreasing sheet thickness enhances the carrier mobility of the GaS nanosheets, contributing to the high photocurrents. Double-peak VBMs are theoretically predicted for ultrathin GaS nanosheets (thickness less than five monolayers), which is found to promote photon absorption. These theoretical and experimental results show that GaS nanosheets are promising materials for high-performance photodetectors on both conventional silicon and flexible substrates.

Keywords:

Gallium sulfide; two-dimensional materials; nanosheets; photodetectors; photoresponsivity