Synthesis And Photoelectric Properties Of Ⅲ-Ⅴ Semiconductor Nanostructures

In recent years, with the demand for high-performance devices increase, III-V semiconductor nanostructures with high electron mobility and unique optical and electrical properties are subject to study. III-V semiconductor nanostructures have been widely used in many areas of the infrared spectral range lasers, detectors, such as national defense, communications, medical, etc. III-V semiconductor nanostructures were synthesized by metal organic chemical vapor deposition(MOCVD), molecular beam epitaxy(MBE) etc. While these devices can be very good for the industry, but the high cost and toxic properties of the precursor are the limits of promotion of large area. This paper studies the synthesized III-V semiconductor nanostructures by conventional chemical vapor deposition(CVD) for the low-cost, easy operation and low toxicity. Ga Sb-Ga In Sb heterojunction nanowires, Ga As Sb alloy nanowires, In As nanobelts and tunable Ga In PSb nanowires have been synthesized and studied. The morphology, composition and structure of III-V semiconductor nanostructures have been studied, the spectrum have been researched by infrared spectroscopy system photoluminescence, the electrical properties of nanowires devices have been studied by semiconductor parameter meter, the infrared region of the device have been studied. The main achievements are summarized as follows.(1) For the first time, the Ga Sb/Ga In Sb p-n heterojunction semiconductor nanowires are synthesized through a controllable chemical vapor deposition(CVD) route. The device based on Ga Sb/Ga In Sb heterojunction nanowires shows good rectifying characteristics. The photoluminescence(PL) of the semiconductor nanowires spectrum have two independent peaks which are from the bandedge emission of the two segments of the NW heterostructures. The photodetector based on single heterojunction nanowire shows excellent light response in the infrared optical communication region(1.55 μm), high external quantum efficiency, high responsivity and short response time properties.(2) Ga As Sb alloy nanowires are synthesized through CVD route, which have a wide bandgap from 0.75 e V to1.424 e V. The PL of Ga As Sb alloy nanowires cover from 870 nm to 1700 nm, so the absorption of light energy and high photoelectric conversion about Ga As Sb alloy nanowires can cover band near-infrared light communication. Ga As0.26Sb0.74 alloy nanowires are synthesized through changing the raw material. The XRD, Raman spectrum and the TEM-EDS demonstrate the element composition. The near-infrared photodetectors were built based on these alloy nanowires. The fabricated devices show a wide response region and have high response in the near-infrared optical communication region(1.31μm). The Ga As Sb nanowire infrared photodetectors have a good parameter with an external quantum efficiency of 105 %, a responsivity of 1.7×103 A/W, which shows promising potential applications in integrated infrared photodetectors and optoelectronics devices or systems.(3) III- V semiconductor nanobelt was successfully synthesized by simple chemical vapor deposition at high temperature for the first time, which is a major breakthrough. In As nanobelts have high-quality crystal structure and fine In/As element ratio. In many papers, it has been reported that In As nanowires are generally grown along the <111>B directions for zinc blende structure or along the <000 1_> for the wurtzite structure. Most of these non-<111>B or <0001_> nanowires are generally defect-free and adopt zinc blende crystal structure. To study the growth mechanism of In As nanobelts, the growing atmosphere of the system has been study and several experiments with different growth time were carried out. The effect of surface-related emissions on the PL of In As nanobelts was also studied by having the nanobelts passivated with ODT. The optoelectronic performance of In As nanobelts photodetector was investigated, the In As nanobelts photodetectors show higher performance than In As nanowires photodetectors. In As nanobelts will become the next new materials for high frequency devices.