Ultrahigh sensitivity and gain white light photodetector based on GaTe/Sn : CdS nanoflake/nanowire heterostructures

Abstract

Optoelectronic diode based on PN heterostructure is one of the most fundamental device building blocks with extensive applications. Here we reported the fabrication and optoelectronic properties of GaTe/Sn : CdS nanoflake/nanowire PN heterojunction photodetectors. With high quality contacts between metal electrodes and Sn : CdS or GaTe, the electrical measurement of GaTe/Sn : CdS hybrid heterojunction under dark condition demonstrates an excellent diode characteristic with well-defined current rectification behavior. The photocurrent increases drastically under LED white light as well as red, green, UV illumination. The on-off ratio of current is about 100 for forward bias and 3000 for reverse bias, which clearly indicates the ultrahigh sensitivity of the heterostructure photodetector to white light. The responsivity and optical gain are determined to be 607 A W(-1) and (1.06-2.16) × 10(5)%, which is higher than previous reports of single GaTe or CdS nanostructures. Combination the Ids-Vds curves under different illumination power with energy band diagrams, we assign that both the light modulation effect under forward and reverse bias and the surface molecular oxygen adsorption/desorption mechanism are dominant to the electrical transport behavior of GaTe/Sn : CdS heterojunction. This heterostructure photodetector also shows good stability and fast response speed. Both the high photosensibility and fast response time described in the present study suggest strongly that the GaTe/Sn : CdS hybrid heterostructure is a promising candidate for photodetection, optical sensing and switching devices.

High-performance photodetectors based on bandgap engineered novel layer GaSe0.5Te0.5 nanoflakes

“…The Raman spectra of GaSe and GaTe were also shown in Fig. 3 13,24,30 The GaSe 0.5 Te 0.5 shows different Raman spectrum from pure GaSe and GaTe. The spectrum prole is similar with that of GaTe.…”

“…21 Up to date, various inorganic semiconductor nanostructures, such as ZnO, CdS, InAs, MoS 2 , GaX (X ¼ Te, Se, S), InSe and In 2 Te 3 , have been used to fabricate photodetectors. [22][23][24] However, the photoresponse gain of GaTe photodetector is low due to the large dark current while the GaSe nanodevices show a high resistivity and very low dark current because of the low mobility. 25 The compound alloy of GaTe and GaSe can improve the photoresponse gain and conduction.…”

Multi-layered MoS2 phototransistors as high performance photovoltaic cells and self-powered photodetectors

“…Optical microscopy (OM) and scanning electron microscopy (SEM) were used to observe the morphology of exfoliated MoS 2 and fabricated devices. The reverse dark current increases exponentially following the equation I～exp(αV), which is usually observed in the p-n diodes due to the recombination tunneling mechanism [42,43]. The multilayer MoS 2 nanodevices were fabricated by following lithography procedure, thermal evaporation and lift-off process.…”

Veritable electronic characteristics in ZnO nanowire circuits uncovered by the four-terminal method at a low temperature

“…The temperature rise leads to an increase in the conductance, which may be due to (i) the reduction of contact resistance and (ii) the desorption of oxygen on the surface 30 and (iii) the thermal activated donors in ZnO. 31 It should be noted that the temperature dependence measurements were undertaken in vacuum to get a stable ambient temperature so oxygen desorption did not play a dominant impact on electron transport in the nanowire. trend while increasing the temperature.…”