Reverse Leakage Current Transport Mechanisms in Ni/Au Al_0.58Ga_0.42N Schottky Type Photodetectors

Abstract

We successfully fabricated the Al0.58Ga0.42N-based solar-blind ultraviolet (UV) Schottky type photodetectors (PDs). The crystalline quality, morphology and dislocation information of the Al0.58Ga0.42N epitaxial layer have been obtained by detailed characterizations of high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscope (TEM). In addition, the responsivity of the PD with cutoff wavelength of 260 nm is 0.15A/W at −5V and 0.12 A/W at 5 V, respectively. Detailed carrier transport models are explored to analyze the I-V-T characteristics measured between 300 and 425 K, in order to provide more information for analyzing the reverse leakage mechanisms in the Al0.58Ga0.42N solar-blind PD. It is convincingly demonstrated that thermionic-field emission and Poole–Frenkel emission can accurately describe the low-bias I-V characteristics and the high-bias I-V characteristics, respectively.

Keywords

• AlGaN
• carrier transport
• Schottky type
• ultraviolet photodetectors