Interfacial photoconductivity effect of type-Ⅰ and type-Ⅱ Sb2Se3/Si heterojunctions for THz wave modulation

作者：曹雪芹; 黄媛媛^*; 席亚妍; 雷珍; 王静; 刘昊楠; 史明坚; 韩涛涛; 张蒙恩; 徐新龙^*

来源：Chinese Physics B, 2023, 32(11): 106-110.

An in-depth understanding of the photoconductivity and photocarrier density at the interface is of great significance for improving the performance of optoelectronic devices. However, extraction of the photoconductivity and photocarrier density at the heterojunction interface remains elusive. Herein, we have obtained the photoconductivity and photocarrier density of 173 nm Sb2Se3/Si(type-Ⅰ heterojunction) and 90 nm Sb2Se3/Si(type-Ⅱ heterojunction) utilizing terahertz(THz) time-domain spectroscopy(THz-TDS) and a theoretical Drude model. Since type-Ⅰ heterojunctions accelerate carrier recombination and type-Ⅱ heterojunctions accelerate carrier separation, the photoconductivity and photocarrier density of the type-Ⅱ heterojunction(21.8×104S·m-1,1.5 × 1015cm-3) are higher than those of the type-Ⅰ heterojunction(11.8×104S·m-1,0.8×1015cm-3). These results demonstrate that a type-Ⅱ heterojunction is superior to a type-Ⅰ heterojunction for THz wave modulation. This work highlights THz-TDS as an effective tool for studying photoconductivity and photocarrier density at the heterojunction interface. In turn, the intriguing interfacial photoconductivity effect provides a way to improve the THz wave modulation performance.

• 单位
  西北大学