Topological Bi₂Se₃/n-GaN Hybrid Structure for Enhanced and Self-Powered UV Photodetectors

Abstract

Recent progress in topological insulating materials predicts a promising future for their applications in developing innovative quantum, electronic, and optoelectronic devices. The integration of topological insulators with technologically important semiconductors can open up different ways to build high-efficiency devices. Here, we have fabricated topological insulator Bi2Se3/GaN hybrid structure-based photodetectors (PDs) and studied their photoresponse characteristics in the ultraviolet (UV) region. Raman and high-resolution X-ray diffraction spectroscopy measurements revealed the formation of the c-axis-oriented rhombohedral crystal structure of the Bi2Se3 film. X-ray photoelectron spectroscopy studies disclosed the formation of a stoichiometric Bi2Se3 thin film on n-GaN. The Bi2Se3 thin film with the magnetotransport property exhibits a metallic nature with an upturn in resistivity below 20 K which possesses a weak antilocalization effect under an applied magnetic field, confirming the topological insulating behavior. Further, we have fabricated metal–semiconductor–metal-type PD devices on the hybrid structure of Bi2Se3/n-GaN, Bi2Se3/n-GaN junction, and pristine n-GaN. The photoresponse measurements have been performed using a UV (355 nm) light source by varying the laser power (1–15 mW) and the external bias (0–5 V). The calculated value of photoresponsivity of the PD devices on the Bi2Se3/n-GaN hybrid structure is found to be seven-fold higher than that of pristine-GaN. Further, it is observed that devices consisting of a Bi2Se3 film and GaN show self-powered UV PD characteristic nature. This study adds a significant step to enhance the performance of UV PDs based on large-area GaN templates by several folds with the help of topological Bi2Se3/GaN hybrid structures.

Growth Mode Transition in Two-Dimensional GaSe on Three-Dimensional GaN/Sapphire Platform: Implication for Self-Powered Photodetection

“…The time-dependent photoresponse characteristics of both films are quite sharp and excellently repeatable with a periodic 30 s of on/off switching frequency (Figure d), suggesting that these fabricated device models are photosensitive to the solar spectrum, especially in the well-defined triangular morphology of the LBL-GaSe layer. It was reported from the literature that the high-band gap and intrinsic n-type properties of GaN might contribute to the performance of such 2D/GaN photodetectors . However, due to the hundreds of nanometer thickness and the preferential lateral transport in both device models, we assume that the contribution of GaN to the total photoresponse signal is the same in the devices and may be ignorable.…”

“…It was reported from the literature that the high-band gap and intrinsic n-type properties of GaN might contribute to the performance of such 2D/GaN photodetectors. 28 However, due to the hundreds of nanometer thickness and the preferential lateral transport in both device models, we assume that the contribution of GaN to the total photoresponse signal is the same in the devices and may be ignorable. Overall, the excellent stability and distinct performance of different growth mode GaSe-based devices could diversify the potential application of Ga-based monochalcogenide once advanced processing and designs in device fabrication are taken into account.…”

Self-Powered FTO/CdSe/Bi2Se3 Photodetector with Bipolar Photoresponse Characteristics

“…With the continuous advancement of information technology, the demand for photoelectric detection is rapidly increasing. − To meet the needs of different application fields, photodetectors based on different structures such as positive-negative (PN), positive-intrinsic-negative (PIN), and metal-semiconductor (MS) junctions have been constructed. Most photodetectors can only produce unidirectional photoelectric signals for specific wavelengths of light, limiting their versatility. − Bipolar photoresponse detectors offer advantages in terms of integration and multifunctionality due to their bipolar output capability and hold promise for applications in biosensors, optical logic gates, and artificial synapse simulation. − …”

2D MXene Electrode-Enabled High-Performance Broadband Photodetector Based on a CVD-Grown 2D Bi2Se3 Ultrathin Film on Silicon

“…Bi 2 Se 3 -based heterostructures, such as WS 2 /Bi 2 Se 3, graphene/Bi 2 Se 3, SnTe/Bi 2 Se 3, Si/Bi 2 Se 3, GaN/Bi 2 Se 3 etc., have been explored to improve the device performance. Despite good responsivity, these heterostructure devices exhibit less detectivity due to high dark currents, which often result from the use of conventional metal electrodes.…”