Rajabali M, Asgharyan H, Naeini V Fadaei, Boudaghi A, Zabihi B, Foroutan M, Mohajerzadeh S
Thin Film and Nanoelectronic Lab, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran.
Division of Machine Elements, Luleå University of Technology, 97187, Luleå, Sweden.
Sci Rep. 2021 Aug 9;11(1):16076. doi: 10.1038/s41598-021-95463-z.
Low concentration phosphorene-based sensors have been fabricated using a facile and ultra-fast process which is based on an exfoliation-free sequential hydrogen plasma treatment to convert the amorphous phosphorus thin film into mono- or few-layered phosphorene sheets. These sheets have been realized directly on silicon substrates followed by the fabrication of field-effect transistors showing the low leakage current and reasonable mobility for the nano-sensors. Being capable of covering the whole surface of the silicon substrate, red phosphorus (RP) coated substrate has been employed to achieve large area phosphorene sheets. Unlike the available techniques including mechanical exfoliation, there is no need for any exfoliation and/or transfer step which is significant progress in shortening the device fabrication procedure. These phosphorene sheets have been examined using transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Raman spectroscopy and atomic-force microscopy (AFM). Electrical output in different states of the crystallization as well as its correlation with the test parameters have been also extensively used to examine the evolution of the phosphorene sheets. By utilizing the fabricated devices, the sensitivity of the phosphorene based-field effect transistors to the soluble L-Cysteine in low concentrations has been studied by measuring the FET response to the different concentrations. At a gate voltage of - 2.5 V, the range of 0.07 to 0.60 mg/ml of the L-Cysteine has been distinguishably detected presenting a gate-controlled sensor for a low-concentration solution. A reactive molecular dynamics simulation has been also performed to track the details of this plasma-based crystallization. The obtained results showed that the imparted energy from hydrogen plasma resulted in a phase transition from a system containing red phosphorus atoms to the crystal one. Interestingly and according to the simulation results, there is a directional preference of crystal growth as the crystalline domains are being formed and RP atoms are more likely to re-locate in armchair than in zigzag direction.
低浓度磷烯基传感器是采用一种简便且超快的工艺制造的，该工艺基于无剥离的顺序氢等离子体处理，将非晶态磷薄膜转化为单层或几层磷烯片。这些片材直接在硅衬底上制成，随后制造场效应晶体管，该晶体管显示出低漏电流和适用于纳米传感器的迁移率。采用涂覆有红磷（RP）的衬底来实现大面积磷烯片，因为它能够覆盖硅衬底的整个表面。与包括机械剥离在内的现有技术不同，无需任何剥离和/或转移步骤，这在缩短器件制造流程方面是一项重大进展。这些磷烯片已通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、拉曼光谱和原子力显微镜（AFM）进行了检测。结晶不同状态下的电输出及其与测试参数的相关性也被广泛用于研究磷烯片的演变。通过使用制造的器件，通过测量场效应晶体管对不同浓度的响应，研究了磷烯基场效应晶体管对低浓度可溶性L-半胱氨酸的灵敏度。在-2.5 V的栅极电压下，已可区分地检测到0.07至0.60 mg/ml的L-半胱氨酸范围，呈现出一种用于低浓度溶液的栅极控制传感器。还进行了反应性分子动力学模拟，以追踪这种基于等离子体结晶的细节。获得的结果表明，氢等离子体赋予的能量导致了从包含红磷原子的系统到晶体系统的相变。有趣的是，根据模拟结果，在形成晶域时晶体生长存在方向偏好，并且RP原子更有可能在扶手椅方向而不是锯齿方向重新定位。
