Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea.
Nanotechnology. 2017 Feb 24;28(8):085201. doi: 10.1088/1361-6528/aa55e4. Epub 2016 Dec 28.
We have demonstrated a few-layer black phosphorus (BP) phototransistor of stable operation in ambient air environment and at near-infrared light (λ = 1550 nm). The air-stable electronic and optoelectronic properties of the few-layer BP phototransistor have been achieved by a proper AlO passivation. The optical identification method and qualitative and quantitative electrical characterizations of the few-layer BP phototransistor in dark state confirmed that the device performance was robust in ambient air, to further chemical treatments, and storage of more than six months. In addition, the low-frequency noise characterizations had revealed that the noise spectral density related to the sensitivity of phototransistor was reduced. Owing to the suppression of interaction between few-layer BP and adsorbates arising from the AlO passivation, a fast rise time of the few-layer BP phototransistor, less than 100 μs, had been observed, demonstrating the intrinsic photoresponse properties of few-layer BP. The low dark current of ∼4 nA at the operation bias and the reasonable responsivity of ∼6 mA W were obtained under the condition lacking adsorbates interactions. Internally, the dark current and responsivity level was tunable by changing the operation bias. Our results are close to the intrinsic properties of the few-layer BP phototransistor, implying that it can be a building block of functioned few-layer BP photodetectors.
我们展示了在近红外光（λ=1550nm）下在环境空气中稳定运行的几层黑磷（BP）光电晶体管。通过适当的 AlO 钝化，实现了具有空气稳定性的几层层 BP 光电晶体管的电子和光电性能。通过对暗态下的几层层 BP 光电晶体管的光学识别方法以及定性和定量电特性的测试，证实了该器件在环境空气中、进一步的化学处理以及超过六个月的储存过程中的性能稳定。此外，低频噪声特性表明，与光电晶体管灵敏度相关的噪声谱密度降低。由于 AlO 钝化抑制了几层层 BP 与吸附物之间的相互作用，观察到几层层 BP 光电晶体管的上升时间快于 100μs，这表明了几层层 BP 的固有光电响应特性。在没有吸附物相互作用的条件下，工作偏置下的暗电流约为 4nA，响应率约为 6mAW，获得了较低的暗电流和合理的响应率。在内部，通过改变工作偏置，可以调节暗电流和响应率水平。我们的结果接近几层层 BP 光电晶体管的固有特性，这意味着它可以成为功能化几层层 BP 光电探测器的构建模块。
