A broadband self-powered UV photodetector of aβ-Ga2O3/γ-CuI p–n junction

The symmetric Ti/Au bi-layer point electrodes have been successfully patterned on theβ-Ga;O;films which are prepared by metal–organic chemical vapor deposition(MOCVD)and theγ-Cu I films which are prepared by spin-coating.The fabricated heterojunction has a large open circuit voltage(Voc)of 0.69 V,desired for achieving self-powered operation of a photodetector.Irradiated by 254-nm ultraviolet(UV)light,when the bias voltage is-5 V,the dark current(Idark)of the device is 0.47 p A,the photocurrent(Iphoto)is-50.93 n A,and the photo-to-dark current ratio(Iphoto/Idark)reaches about 1.08×10;.The device has a stable and fast response speed in different wavelengths,the rise time(τr)and decay time(τd)are 0.762 s and 1.741 s under 254-nm UV light illumination,respectively.While theτr andτd are 10.709 s and7.241 s under 365-nm UV light illumination,respectively.The time-dependent(I–t)response(photocurrent in the order of10-10 A)can be clearly distinguished at a small light intensity of 1μW·cm;.The internal physical mechanism affecting the device performances is discussed by the band diagram and charge carrier transfer theory.

A broadband self-powered UV photodetector of a β-Ga2O3/γ-CuI p-n junction

The symmetric Ti/Au bi-layer point electrodes have been successfully patterned on the β-Ga₂O₃ films which are prepared by metal-organic chemical vapor deposition (MOCVD) and the γ-CuI films which are prepared by spin-coating. The fabricated heterojunction has a large open circuit voltage (V_oc) of 0.69 V, desired for achieving self-powered operation of a photodetector. Irradiated by 254-nm ultraviolet (UV) light, when the bias voltage is -5 V, the dark current (I_dark) of the device is 0.47 pA, the photocurrent (I_photo) is -50.93 nA, and the photo-to-dark current ratio (I_photo/I_dark) reaches about 1.08×10⁵. The device has a stable and fast response speed in different wavelengths, the rise time (τ_r) and decay time (τ_d) are 0.762 s and 1.741 s under 254-nm UV light illumination, respectively. While the τ_r and τ_d are 10.709 s and 7.241 s under 365-nm UV light illumination, respectively. The time-dependent (I-t) response (photocurrent in the order of 10^-10 A) can be clearly distinguished at a small light intensity of 1 μW·cm^-2. The internal physical mechanism affecting the device performances is discussed by the band diagram and charge carrier transfer theory.