In this paper, we describe the fabrication and characterization of a GaN-based light-emitting diode (LED) on a GaN-on-silicon platform. A freestanding membrane structure eliminates the absorption of the emitted light by a silicon substrate and reduces the number of confined optical modes, leading to higher photoluminescence intensity. Compared with an LED with a silicon substrate, the current-voltage characteristics of a freestanding membrane LED demonstrate a lower turn-on voltage and a steeper current-voltage profile. Both anomalous positive capacitance peak and negative capacitance are observed in the capacitance-voltage measurements, which correspond well to the current-voltage characteristics. The measured electroluminescence intensity is significantly increased for a freestanding membrane LED. These experimental results show that our proposed substrate removal technology is promising for the fabrication of a high-performance membrane LED for diverse applications.