Synthesis of single-crystalline GeS nanoribbons for high sensitivity visible-light photodetectors

Abstract

Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. Structural characterization revealed that the nanoribbons grow along [011] direction with thickness of 20~50 nm, width of several micrometers and length of hundreds of micrometers. The GeS nanoribbons show a p-type behavior verified from field effect transport measurement. The nanoribbon photodetectors respond to the entire visible incident light with response edge around 750 nm consistent with the band gap absorption of GeS. Strong nonlinear light-intensity-dependent response was observed between the measured illumination intensity from 0.25 to 212 µW/cm 2 . Under 530 nm light illumination, the maximum responsivity and external quantum efficiency are 139.9 A/W and 32730%, respectively. These results indicate that GeS nanoribbons are promising semiconducting nanomaterial for high performance broadband visible-light sensing applications. Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. The nanoribbon photodetectors respond to the entire visible incident light with response edge around 750 nm with high reponsivity, indicating its promising application for high performance broadband visible-light photo-detecting.

Flexible Near‐Infrared Plastic Phototransistors with Conjugated Polymer Gate‐Sensing Layers

“…It is noted that the similar trend of responsivity was obtained at the high P IN (470.5 µW cm −2 ) but the R C/M values were significantly lower than those at the low P IN (see Figure S14, Supporting Information). Therefore, it is understood that the increased charge recombination loss at a high light intensity, which is typical in the case of conventional organic phototransistors with the channel sensing layers, may also affect the responsivity of the present devices with the conjugated polymer gate‐sensing layers …”

Photoelectric Detectors Based on Inorganic p‐Type Semiconductor Materials

“…Various GeS nanostructures have been reported, such as nanosheets, nanoflowers, nanoparticles, 1D–2D composite structures, etc . Lan et al synthesized crystalline GeS nanoribbons by chemical vapor deposition and explored the photoresponse properties of nanostructured single‐crystalline GeS . The GeS nanoribbons exhibit a p‐type behavior as demonstrated from the field effect transport measurement.…”

“…d) Rise and decay rate of the photocurrent for the nanoribbon photodetector. Reproduced with permission . Copyright 2015, Royal Society of Chemistry.…”

“…Among various transition metal oxides, cupric oxide (CuO), as a p‐type semiconductor with a narrow bandgap of 1.2–1.5 eV, has been considered as a very promising material for photovoltaic, optoelectronic, and catalytic applications. The bandgap value for CuO is significantly lower than that of other common oxides, and this makes it suitable candidate material for detecting infrared (IR) light …”

Polarization Photoelectric Conversion in Layered GeS

“…On the other hand, concerning the quantum confinement effect, a dramatic enhancement of excitonic effect including electron–hole (e – h) interactions will dominate optical responsivity in many low‐dimensional graphene‐like and 2D‐layered materials . The dimensionality‐induced excitonic effects have revived the research attention on layered germanium sulfide (GeS) from high‐pressure phase studies to a potential application in designing solar cells . However, from the theoretical background, the detail of optical transitions within a single observed broaden resonance is easy to be clouded with sophisticated convolution of close‐lying excitonic features.…”