Suspended few-layer GaS photodetector with sensitive fast response

•The suspended few-layered GaS photodetector exhibits sensitive fast response in a wide spectrum range (300–628 nm).•The maximum responsivity of ∼ 1730 A/W and a response speed < 9 μs is obtained in 405 nm.•Photoconductance effect plays the dominant role with the comparative experiments and band theory analysis.