Fig. 1. Crystal structure and material characterization results. (a) TlGaS₂ crystal structure; (b) optical microscope photos of nanosheets; (c) AFM test; (d) Raman test result; XPS test results of elements (e) Tl and (f) Ga

Fig. 2. Theoretical calculation and absorption spectrum test results. (a) Energy band structure of TlGaS₂ bulk material; (b) density of states at band edge; (c) measured absorption spectrum of TlGaS₂ nanosheet

Fig. 3. Test results of photoelectric performances of TlGaS₂ photodetector. (a) Structural diagram of TlGaS₂ detector; (b) output curves under dark state and different wavelength light irradiation conditions with optical microscope photo of device shown in insert; (c) spectral response range of detector; (d) responsivity and specific detection rate versus wavelength; (e) transient response test results under different optical power densities at 360 nm; (f) photocurrent versus optical power density

Fig. 4. Working performances and principle of TlGaS₂ photodetector. (a) Response speed; (b) noise performance under weak field; (c) air stability; (d) photocurrent two-dimensional plane scanning test; (e)(f) working principle of detector