Fabrication of single Ga-doped ZnS nanowires as high-gain photosensors by focused ion beam deposition

Abstract

ZnS nanowires were synthesized via a vapor-liquid-solid mechanism and then fabricated into a single-nanowire field-effect transistor by focused ion beam (FIB) deposition. The field-effect electrical properties of the FIB-fabricated ZnS nanowire device, namely conductivity, mobility and hole concentration, were 9.13 Ω cm, 13.14 cm V sand 4.27 × 10 cm, respectively. The photoresponse properties of the ZnS nanowires were studied and the current responsivity, current gain, response time and recovery time were 4.97 × 10 A W, 2.43 × 10, 9 s and 24 s, respectively. Temperature-dependent I-V measurements were used to analyze the interfacial barrier height between ZnS and the FIB-deposited Pt electrode. The results show that the interfacial barrier height is as low as 40 meV. The energy-dispersive spectrometer elemental line scan shows the influence of Ga ions on the ZnS nanowire surface on the FIB-deposited Pt contact electrodes. The results of temperature-dependent I-V measurements and the elemental line scan indicate that Ga ions were doped into the ZnS nanowire, reducing the barrier height between the FIB-deposited Pt electrodes and the single ZnS nanowire. The small barrier height results in the FIB-fabricated ZnS nanowire device acting as a high-gain photosensor.

Direct growth of germanium nanowires on glass

“…In [17], the authors discuss as a possible explanation of this advantageous feature, the intrinsic low resistivity of FIBID-Pt and the Ga-ion induced local implantation of the NW under the Pt contact. This is consistent with the results reported on FIBID-Pt contacts on Si NWs [18], on ZnS NWs [19] and on ZnO NWs [20].The ohmic nature of Pt contacts to NWs allows to assume that the resistance measured in two-point configuration is dominated by the NW resistance and to derive an estimation of the resistivity of single NWs.…”

Progress in ultraviolet photodetectors based on II–VI group compound semiconductors

“…Some UVPDs based on 1D II–VI group semiconductors exhibit an ultra-high photoresponsivity (>10 5 A W −1 ), such as nanoribbons, nanobelts, and nanowires. 10,43,44,49,63 After optimizing the device structure, the photodetectors often show a faster response speed. 10,23,46,57,107 We summarize the important parameters of UVPDs based on various types of II–VI group semiconductor nanostructures in Table 2.…”

“…This review is primarily focused on UVPDs based on II–VI group semiconductors. The device geometry based on II–VI group semiconductors mainly includes photo-conductive type, 19,43–57 heterojunctions, 10,52,58–62 and phototransistors 62–64 (Fig. 2).…”

Nanomanufacturing of biopolymers using electron and ion beams

“…Focused-ion beams (FIB) have become increasingly popular for high-resolution nanofabrication and microelectronics combining high resolution with great precision. FIB finds its use in various modes such as maskless milling [83][84][85] and deposition [86][87][88], ion implantation [89,90], exposure of resist [72], microsystem technology inspection [91], and failure analysis [92,93]. This versatility permits its wide applications where other techniques are not suitable, or are too difficult and complicated.…”