Recent progress on infrared photodetectors based on InAs and InAsSb nanowires

Advancements and Challenges in the Integration of Indium Arsenide and Van der Waals Heterostructures

The strategic integration of low-dimensional InAs-based materials and emerging van der Waals systems is advancing in various scientific fields, including electronics, optics, and magnetics. With their unique properties, these InAs-based van der Waals materials and devices promise further miniaturization of semiconductor devices in line with Moore's Law. However, progress in this area lags behind other 2D materials like graphene and boron nitride. Challenges include synthesizing pure crystalline phase InAs nanostructures and single-atomic-layer 2D InAs films, both vital for advanced van der Waals heterostructures. Also, diverse surface state effects on InAs-based van der Waals devices complicate their performance evaluation. This review discusses the experimental advances in the van der Waals epitaxy of InAs-based materials and the working principles of InAs-based van der Waals devices. Theoretical achievements in understanding and guiding the design of InAs-based van der Waals systems are highlighted. Focusing on advancing novel selective area growth and remote epitaxy, exploring multi-functional applications, and incorporating deep learning into first-principles calculations are proposed. These initiatives aim to overcome existing bottlenecks and accelerate transformative advancements in integrating InAs and van der Waals heterostructures.

Mid-infrared tunable absorber based on an Ag/SiO2/VO2/Ag/VO2 multilayer structure and its molecular sensing capability

We present a design of middle-infrared modulation absorbers based on vanadium dioxide (VO2). By using the electron beam evaporation technique, the Ag/SiO2/VO2/Ag/VO2 multilayer structure can achieve double band strong absorption in the mid-infrared, and dynamically adjust the absorption performance through VO2. The simulation results demonstrate a remarkable absorption rate of 91.8% and 98.9% at 9.09 µm and 10.25 µm, respectively. The high absorption is elucidated by analyzing the field strength distribution in each layer. Meanwhile, based on the phase change characteristics of VO2, the absorber has exceptional thermal regulation, with a remarkable 78% heat regulation range in the mid-infrared band. The size altering of the absorbing layer is effective in enhancing and optimizing the structure's absorption performance. The structure is used to characterize probe molecules of CV and R6 G by mid-infrared spectroscopy, which illustrates an impressive limit of detection (LOD) of 10-7 M for both substances. These results provide valuable insights for designing future high-performance tunable optical devices.

Large-Composition-Range Pure-Phase Homogeneous InAs1-xSbx Nanowires

Narrow bandgap InAs_1-xSb_x nanowires show broad prospects for applications in wide spectrum infrared detectors, high-performance transistors, and quantum computation. Realizing such applications requires a fine control of the composition and crystal structure of nanowires. However, the fabrication of large-composition-range pure-phase homogeneous InAs_1-xSb_x nanowires remains a huge challenge. Here, we first report the growth of large-composition-range stemless InAs_1-xSb_x nanowires (0 ≤ x ≤ 0.63) on Si (111) substrates by molecular beam epitaxy. We find that pure-phase InAs_1-xSb_x nanowires can be successfully obtained by controlling the antimony content x, nanowire diameter, and nanowire growth direction. Detailed energy dispersive spectrum data show that the antimony is uniformly distributed along the axial and radial directions of InAs_1-xSb_x nanowires and no spontaneous core-shell nanostructures form in the nanowires. On the basis of field-effect measurements, we confirm that InAs_1-xSb_x nanowires exhibit good conductivity and their mobilities can reach 4200 cm² V^-1 s^-1 at 7 K. Our work lays the foundation for the development of InAs_1-xSb_x nanowire optoelectronic, electronic, and quantum devices.

High-Performance Room-Temperature UV-IR Photodetector Based on the InAs Nanosheet and Its Wavelength- and Intensity-Dependent Negative Photoconductivity

Low-dimensional narrow-band-gap III-V semiconductors have great potential in high-performance electronics, photonics, and quantum devices. However, high-performance nanoscale infrared photodetectors based on isolated two-dimensional (2D) III-V compound semiconductors are still rare. In this work, we demonstrate a new type of photodetector based on the InAs nanosheet. The photodetector has high optoelectronic response in the ultraviolet-infrared band (325-2100 nm) at room temperature. The high-performance photodetector has very high responsivity (∼1231 A/W), EQE (2.2 × 10⁵ %), and detectivity (5.46 × 10¹⁰ Jones) to 700 nm light at low operating voltage (∼0.1 V). These results indicate that 2D InAs nanosheet devices have great potential in nano-optoelectronic devices and integrated optoelectronic devices. In addition, we observe for the first time that the InAs nanosheet devices have a negative photoconductivity (NPC) that is not only affected by the wavelength but also related to the optical power intensity of the light. After analyzing experimental data, we propose that the origin of the NPC may come from electron trapping, and two competing mechanisms of optical absorption and the photogating effect in the photoelectric response process cause the dependence on the light wavelength and optical power intensity.

Time dependence of negative and positive photoconductivity for Si δ-doped AlGaAs/InGaAs/AlGaAs quantum well under various temperatures and various incident photon energies and intensities

Si δ-doped AlGaAs/InGaAs/AlGaAs quantum well (QW) structure is commonly adopted as one of the core elements in modern electric and optoelectronic devices. Here, the time dependent photoconductivity spectra along the active InGaAs QW channel in a dual and symmetric Si δ-doped AlGaAs/InGaAs/AlGaAs QW structure are systematically studied under various temperatures (T = 80-300 K) and various incident photon energies (E _in = 1.10-1.88 eV) and intensities. In addition to positive photoconductivity, negative photoconductivity (NPC) was observed and attributed to two origins. For T = 180-240 K with E _in = 1.51-1.61 eV, the trapping of the photo-excited electrons by the interface states located inside the conduction band of InGaAs QW layer is one of the origins for NPC curves. For T = 80-120 K with E _in = 1.10-1.63 eV, the photoexcitation of the excess 'supersaturated' electrons within the active InGaAs QW caused by the short cooling process is another origin.

Anomalous Photoelectrical Properties through Strain Engineering Based on a Single Bent InAsSb Nanowire

In this study, electrical and photoresponse properties of bent InAsSb nanowires (NWs) were investigated to explore the impact of bending strain on the photoelectrical properties. The corresponding morphological and structural observations demonstrate the phase segregation and strain in the core-shell zinc-blende-structured InAsSb NWs. It is found that the device made of bent InAsSb individual NW presents the switch from negative photoconductivity (NPC) and positive photoconductivity (PPC). The transformation between NPC and PPC can be achieved by not only gate voltage but also bias voltage, indicating the potential in the pervasive computing of bent InAsSb NWs. This work combines the semiconductor properties, light excitation, and piezoelectric effect of the InAsSb NWs, providing new ideas for next-generation photoelectrical nanodevices.

Surface-States-Modulated High-Performance InAs Nanowire Phototransistor

We report a high-performance InAs nanowire phototransistor with the photoresponse mechanism governed by the gate-controlled surface states. Detailed characterizations suggest that the high density of surface defect states of the InAs nanowire can capture electrons from the nanowire core to form negative surface charge centers. Before and after light illumination, nanowire surface states undergo processes of capturing and neutralizing the electrons, respectively. This leads to an increase in the concentration and mobility of electrons after light illumination, which endows the device with remarkable photoresponsivity. After modulating the surface states through gate voltage and surface passivation, significantly high responsivity of up to 4.4 × 10³ A/W and gain of up to 2.7 × 10³ under the illumination of light at the wavelength of 2000 nm are obtained, putting our devices among the high-performance short-wave infrared nanowire photodetectors. This work provides an important reference for understanding the surface effects of nanomaterials and enhancing the performance of nanophotodetectors by modulating the surface states.