Antimonide

About: Antimonide is a research topic. Over the lifetime, 972 publications have been published within this topic receiving 10981 citations. The topic is also known as: antimonides.

Devices and desires in the 2-4 mu m region based on antimony-containing III-V heterostructures grown by MOVPE

Abstract: The growth, by MOVPE, of a range of antimonide-based material systems suitable for providing devices responsive to 2-4 mu m wavelength radiation is reported. Photodetectors with external quantum efficiencies of 60% at 2.2 mu m have been fabricated from an InGaSb homojunction. In order to examine the possibility of tuning the wavelength of emission or detection by using a strained single quantum well (SSQW) of InGaSb/GaSb this has been grown in the depletion region of a GaSb homojunction. These novel heterostructures have been grown to produce devices without the need for conventional doping. Using the crossed-gap alignment of InAs/GaSb the authors can form a diode-like structure. The most promising devices have a turn-on voltage VTO of 0.7 V (1mA), and a typical reverse voltage VR=-12 V (0.1 mA) and a best VR of -12 V (10 mu A) for a 100 mu m diameter device with some evidence of avalanche breakdown in the structure. Abrupt doping junctions have been formed between GaSb and GaAs:Si substrates. The mismatch between the layers is ameliorated by using a low-temperature buffer layer to improve the interface. Avalanche breakdown starts at -4.5 V in these structures and reverse bias currents of <10 mu A at up to 2 V from unintentionally doped GaSb (uGaSb) with a carrier concentration of 1016 cm-3 p. Schottky barriers are an alternative to p/n junctions, but they cannot be made at all on uGaSb because of the low barrier height, which is of the order of 0.2 eV. We have overcome this problem using a thin capping layer of highly dislocated GaAs. Surprisingly this has been successful for both regrowth on older structures and contiguous in situ growth.

Photovoltaic neurointerface based on aluminum antimonide nanocrystals

Abstract: Light activated modulation of neural activity is an emerging field for the basic investigation of neural systems and development of new therapeutic methods such as artificial retina. Colloidal inorganic nanocrystals have great potential for neural interfaces due to their adjustable optoelectronic properties via high-level structural, compositional, and size control. However, toxic heavy metal content (e.g., cadmium, mercury), electrochemical coupling to the cells and low photon-to-current efficiency limit their effective use. Here, we introduce the use of aluminum antimonide (AlSb) nanocrystals as the cell interfacing layer for capacitive neural stimulation in the blue spectrum. We demonstrate successful photostimulation of primary hippocampal neurons below ocular safety limits. In addition, our device shows high biocompatibility in vitro and passive accelerated ageing tests indicate a functional lifetime over 3 years showing their feasible use for chronic implants. We demonstrate that nanocrystal biointerfaces hold high promise for future bioelectronics and protheses. Artificial retinas require materials and devices that can interface with the nervous system. Here, aluminum antimonide colloidal nanocrystals are used as the interfacing layer with a biological medium, showing a fast photoresponse of 55 µs and a suggested operational lifetime of 36 months.

Can antimonide-based nanowires form wurtzite crystal structure?

Abstract: The epitaxial growth of antimonide-based nanowires has become an attractive subject due to their interesting properties required for various applications such as long-wavelength IR detectors. The studies conducted on antimonide-based nanowires indicate that they preferentially crystallize in the zinc blende (ZB) crystal structure rather than wurtzite (WZ), which is common in other III-V nanowire materials. Also, with the addition of small amounts of antimony to arsenide- and phosphide-based nanowires grown under conditions otherwise leading to WZ structure, the crystal structure of the resulting ternary nanowires favors the ZB phase. Therefore, the formation of antimonide-based nanowires with the WZ phase presents fundamental challenges and is yet to be explored, but is particularly interesting for understanding the nanowire crystal phase in general. In this study, we examine the formation of Au-seeded InSb and GaSb nanowires under various growth conditions using metalorganic vapor phase epitaxy. We address the possibility of forming other phases than ZB such as WZ and 4H in binary nanowires and demonstrate the controlled formation of WZ InSb nanowires. We further discuss the fundamental aspects of WZ growth in Au-seeded antimonide-based nanowires.

New developments in mid-infrared Sb-based lasers

Abstract: A number of different approaches are being investigated to obtain high-performance mid-infrared (2-5 μm) diode lasers for applications such as infrared lidar, remote sensing and environmental monitoring. They include laser heterostructures based on interband transitions in quantum-well or superlattice active region, and quantum cascade structures based on unipolar intersubband transitions. The Sb-containing structures, employing GaSb, InAs, AlSb and related alloys, are focusing actually much attention. Significant improvements in the molecular beam epitaxy of these alloys make possible now the growth of laser antimonide structures of high structural quality. Excellent performances have been reported at = 2 μm from GaInAsSb /AlGaAsSb and at = 3.5 μm from InAsSb/InAlAsSb type-I quantum-well diode lasers. Type-II (staggered alignment) GaInAsSb/GaSb and type-III (broken gap alignment) InAs/Ga(In)Sb strained multiquantum-well lasers are promising material systems for mid-infrared sources, due to their large conduction and valence band offsets, the potential of Auger process suppression and the enhancement of the electron-hole optical coupling by wave function engineering. Besides high performance interband quantum cascade lasers operating at room temperature with negligible current leakage and high output power can be designed from Sb-containing type-III structures.

Synthesis and x-ray characterization of sputtered bi-alkali antimonide photocathodes

Abstract: Advanced photoinjectors, which are critical to many next generation accelerators, open the door to new ways of material probing, both as injectors for free electron lasers and for ultra-fast electron diffraction. For these applications, the nonuniformity of the electric field near the cathode caused by surface roughness can be the dominant source of beam emittance. Therefore, improving the photocathode roughness while maintaining quantum efficiency is essential to the improvement of beam brightness. In this paper, we report the demonstration of a bi-alkali antimonide photocathode with an order of magnitude improved roughness by sputter deposition from a K2CsSb sputter target, using in situ and operando X-ray characterizations. We found that a surface roughness of 0.5 nm for a sputtered photocathode with a final thickness of 42 nm can be achieved while still yielding a quantum efficiency of 3.3% at 530 nm wavelength.