Ternary CuIn₇Se₁₁: Towards Ultra‐Thin Layered Photodetectors and Photovoltaic Devices

Abstract

2D materials have been widely studied over the past decade for their potential applications in electronics and optoelectronics. In these materials, elemental composition plays a critical role in defining their physical properties. Here we report the first successful synthesis of individual high quality CuIn 7 Se 11 (CIS) ternary 2D layers and demonstrate their potential use in photodetection applications. Photoconductivity measurements show an indirect bandgap of 1.1 eV for few-layered CIS, an external quantum efficiency of 88.0 % with 2 V bias across 2 µm channel with and a signal-to-noise ratio larger than 95 dB. By judicious choice of electrode materials, we demonstrate the possibility of layered CIS-based 2 2D photovoltaic devices. This study examines this ternary 2D layered system for the first time, demonstrating the clear potential for layered CIS in 2D material-based optoelectronic device applications.

Fast photoresponse and high detectivity in copper indium selenide (CuIn 7 Se 11 ) phototransistors

“…For example, in a previous report [12], it was shown that for 3-4 layers devices of similar material, a responsivity of 0.4 AW -1 with external quantum efficiency of 88 %, and response times ~ of milliseconds (ms) can be obtained. Whereas for multilayer devices, as shown in this investigations responsivity of > 10 AW -1 with external quantum efficiency 10 3 % and response times ~ of microseconds (µs) can be obtained.…”

“…For fabrication the FET devices, CuIn 7 Se 11 were exfoliated from bulk crystal grown using chemical vapor transport technique [12], on clean pieces of commercially available oxidized silicon wafers (with SiO 2 thickness of ~ 300 nm), as shown in supplementary information figure S1. Metal contact of Chromium (Cr ~ 20 nm) and Gold (Au ~ 240 nm) were deposited on asexfoliated multilayer flakes of CuIn 7 Se 11 by using a house built thermal evaporation system through a metal shadow mask.…”

Electric Double Layer Field-Effect Transistors Using Two-Dimensional (2D) Layers of Copper Indium Selenide (CuIn7Se11)

“…A detailed synthesis of CuIn 7 Se 11 has been reported elsewhere [27]. In a nutshell, single crystals of CuIn 7 Se 11 were grown via a typical melting and recrystallization process with Cu 2 Se and In 2 Se 3 as precursors.…”

“…Such a layered structure, therefore, can be exfoliated into ultra-thin conductive channel materials (not possible for extensively investigated thin films). For example, a 2D-layered structure of ternary copper indium selenide (CIS)-specifically, CuIn 7 Se 11 (γ-phase of CIS)-has shown to have excellent electronic and optoelectronic properties with field-effect mobility reaching~37 cm 2 V −1 s −1 along with photo-responsivity of~32 A W −1 and a response time~9 µs [27,28]. However, most of these materials are investigated in the light of FET-based devices with conventional SiO 2 gates.Here, we show that by constructing an electric double layer field-effect transistor (EDL-FET) using CuIn 7 Se 11 as the channel material and an ionic liquid electrolyte (1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF 6 )) as the gate terminal can provide FET devices with further tunability.…”

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

“…These materials may nd important applications. 11,12 More exploration about III-VI materials is motivated by their anisotropic crystallography characteristics and intriguing optical or optoelectronic properties. 13,14 The p-type GaTe with direct band gap of 1.7 eV, p-type GaSe with indirect bandgap of 2.0-2.1 eV and direct bandgap of 2.12-2.15 eV, n-type GaS with indirect bandgap of 2.5-2.6 eV and direct bandgap of 3.0-3.1 eV, can be used as building blocks for novel van der Waals p-n heterostructures, visible light emitter and broadband terahertz pulses generator.…”