Broadband Photodetection of GeSe Films of Vertically Grown Nanoflakes

GeSe films formed with vertically grown nanoflakes were synthesized by a chemical vapor deposition (CVD) method. The GeSe films display good photoresponse over a broad range of wavelengths from ultraviolet (UV) to visible to near-infrared (NIR) with on/off switching property. The photocurrent values are substantially decreased upon increasing gate voltage, clearly verifying the p-type nature of GeSe films. The optoelectronic properties of the GeSe films at room temperature were characterized, yielding responsivity Rλ ∼ 63 mA/W, external quantum efficiency (EQE) ∼ 8.9%, and specific detectivity (D*) ∼ 8 × 108 jones (measured at λ = 900 nm, P = 1.5 W/m2, Vg = 0 V, and Vds = 2 V). Moreover, these parameters are gate-tunable, showing the promise of GeSe thin films of vertically grown nanoflakes as a versatile photodetector.