Based on an electrophoretic deposition (EPD)-gate approach, a Pt/AlGaN/GaN heterostructure field-effect transistor (HFET) is fabricated and investigated at higher temperatures. The Pt/AlGaN interface with nearly oxide-free is verified by an Auger Electron Spectroscopy (AES) depth profile for the studied EPD-HFET. This result substantially enhances device performance at room temperature (300 K). Experimentally, the studied EPD-HFET exhibits a high turn-on voltage, a well suppression on gate leakage, a superior maximum drain saturation current, and an excellent extrinsic transconductance. Moreover, the microwave performance of an EPD-HFET is demonstrated at room temperature. Consequentially, this EPD-gate approach gives a promise for high-performance electronic applications. (C) 2016 Elsevier Ltd. All rights reserved.