Deep-ultraviolet and visible dual-band photodetectors by integrating Chlorin e6 with Ga₂O₃

Abstract

Gallium oxide (Ga2O3) is a promising material for deep-ultraviolet (DUV) detection. In this work, Chlorin e6 (Ce6) has been integrated with Ga2O3 to achieve a DUV and visible dual-band photodetector, which can achieve multiple target information and improve the recognition rate. The photodetector shows two separate response bands at 268 nm and 456 nm. The DUV response band has a responsivity of 9.63 A/W with a full width at half maximum (FWHM) of 54.5 nm; the visible response band has a responsivity of 1.17 A/W with an FWHM of 45.3 nm. This work may provide a simple way to design and fabricate photodetectors with dual-band response.

Fast-speed self-powered PEDOT:PSS/α-Ga2O3 nanorod array/FTO photodetector with solar-blind UV/visible dual-band photodetection

“…Besides, the photoresponse speed is much faster than the non-selfpowered β -Ga 2 O 3 /MoS 2 /Ce6 DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by built-in electric field in the depletion regions of PEDOT:PSS/α-Ga 2 O 3 heterojunction. [19] Therefore, the fast-speed self-powered α-Ga 2 O 3 solar-blind UV/visible dualband photodetectors can be demonstrated through cheap and simple processes including hydrothermal, annealing and spin coating. β -Ga 2 O 3 /MoS 2 /Ce6 a DUV/visible dual band 9.63 × 10 3 @268 nm@8 V; 1.17 × 10 3 @456 nm@8 V 2.0109@254 nm@5 V; 3.8372@450 nm@5 V [19] Pt/Na 2 SO 4 solution/ α-Ga 2 O 3 nanorod array/FTO b UVC 1.44@254 nm 0.17@254 nm [21] Cu 2 O microsphere/ α-Ga 2 O 3 nanorod array/FTO b UVC/UVA dual band 0.42@254 nm; 0.57@365 nm 10.1@254 nm; 0.159@365 nm [22] Pt/NaOH solution/ α-Ga 2 O 3 nanorod array/FTO b UVC 0.21@254 nm 0.056@254 nm [23] Graphene-Ag nanowire/ α-Ga 2 O 3 /β -Ga 2 O 3 nanorod array/FTO b UVC 0.26@254 nm 1.63/6.79@254 nm [24] PEDOT:PSS/α-Ga 2 O 3 nanorod array/FTO b UVC/visible dual band 0.18@235 nm; 0.004@520 nm 0.102@250 nm; 0.136@540 nm this work a non-self-powered photodetector, b self-powered photodetector.…”

“…[15][16][17][18] For example, Ce6 (a derivative of natural chlorophyll) was coated on β -Ga 2 O 3 /MoS 2 to realize β -Ga 2 O 3 /MoS 2 /Ce6 DUV/visible dual-band photodetectors with excellent photoresponse properties. [19] Nevertheless, the fabrication processes were complex, including the growth of β -Ga 2 O 3 film on Si by PECVD, the growth of MoS 2 by CVD and the further transfer of MoS 2 on the β -Ga 2 O 3 film. Besides, the dual-band photodetectors should be operated under bias voltages with a slow response time of > 2 s. Therefore, more simple fabrication processes should be explored to realize solar-blind UV/visible dual-band photodetectors in a power-saved operation mode with faster response time.…”

“…Besides, the photoresponse speed (0.136 s at 540 nm and 0.102 s at 250 nm) is much faster than the β -Ga 2 O 3 /MoS 2 /Ce6 DUV/visible dual-band photodetectors owing to the fast-speed separation of photogenerated carries by built-in electric field in the depletion regions of PEDOT:PSS/α-Ga 2 O 3 heterojunction. [19] Therefore, fast-speed self-powered α-Ga 2 O 3 solar-blind UV/visible dualband photodetectors are anticipated to be realized by simple fabrication processes for the applications of multiple target tracking, imaging, machine vision and communication.…”

High Performance of Zero-Power-Consumption MOCVD-Grown β-Ga2O3-Based Solar-Blind Photodetectors with Ultralow Dark Current and High-Temperature Functionalities

“…Unlike commercially available UV PDs based on narrow-band-gap semiconductor materials such as Si and GaAs, they do not require any additional optical filter or large cooling systems. ,− Among these, β-Ga 2 O 3 has received a lot of attention because of its excellent material properties such as an ultrawide direct band gap of about 4.9 eV, superior radiation hardness, high chemical and thermal stability, and high absorption coefficient (>10 5 cm –1 ). In addition, to date, high-crystalline-quality Ga 2 O 3 single-crystal substrates, epilayers, and thin films could be grown quite maturely and cost-effectively by various melt growth and thin-film techniques including edge-defined film-fed growth (EFG), Czochralski (CZ) method, MOCVD, halide vapor-phase epitaxy (HVPE), atomic layer deposition (ALD), pulsed laser deposition (PLD), and molecular beam epitaxy (MBE) without any doping complexity in comparison to other wide and ultrawide-band-gap semiconductor materials. − Apart from the β-phase, DUV PDs have also been demonstrated on amorphous and ε-phases of Ga 2 O 3 . ,,− …”

Suppression of persistent photoconductivity in high gain Ga2O3 Schottky photodetectors*

“…Recently, Ga 2 O 3 and related materials have attracted widespread attention due to their potential applications in optoelectronic and microelectronic devices. [1][2][3][4][5][6][7][8][9] Although significant progress has been made in the research of Ga 2 O 3 based devices, the manipulation and understanding of its defects and related physical characteristics still demand further research, [10][11][12][13][14][15][16][17][18] for example, the defect-related photoconductivity gain and persistent photoconductivity (PPC) observed in Ga 2 O 3 photodetectors. [19][20][21][22][23][24][25] The photoconductive gain increases the responsivity of the device, which is conducive to the detection of weak light, while PPC increases the response recovery time of the device, which is not conducive to the detection of high-frequency switching light.…”