Enhanced performance of Cu/P-type GaN triboelectric nanogenerator through heterojunction

The metal/semiconductor triboelectric nanogenerator (TENG) is known for its minimal internal resistance, high energy collection efficiency, stability, and affordability. The focus of research has been on enhancing the performance of metal/semiconductor DC TENG and understanding the formation mechanism of its current. At present, there are few reports that specifically analyze the surface electric field and the built-in electric field separately to optimize TENG performance through adjustments to the built-in electric field. In this study, we investigate the influence of the built-in electric field on the performance of Cu/P-type GaN TENG, with carrier concentration at 1 × 10⁷ cm⁻³ and contact area at 1.5 × 1.5 cm². We modify the P-type GaN wafer structure by introducing a heterojunction to alter the strength of the built-in electric field. Our experimental results demonstrate a significant improvement in TENG performance when using a heterojunction GaN wafer2 (GaN/AlGaN/P-type GaN) in combination with a copper sheet, as compared to a homojunction GaN wafer1 (GaN/U GaN/P-type GaN) with a copper sheet. Specifically, the short circuit current (I_sc) increases from 20 to 30 μA, and the open circuit voltage (V_oc) increases from 8 to 15 V. Therefore, we propose a novel approach for adjusting the performance of metal/semiconductor TENG based on optimizing the built-in electric field, which has the potential to enhance the overall efficiency of these devices.