Synthesis And Optoelectronic Properties Of InGaAs Nanostructures

InGaAs is a typical III-V alloy semiconductor. The bandgaps of InGaAs range from 0.35 to 1.42 e V and it remains a direct-gap material over its entire composition range at room temperature. Due to the tunability of bandgap, high carrier mobilities and low leakage current, InGaAs semiconductor nanomaterials find wide application.At present, research about InGaAs nanostructure mainly focus on the growth of nanowire and optoelectronic devices. In the past few years, the reports of InGaAs optoelectronic devices include near infrared lasing, solar cell and transistor. In this paper, the high quality InGaAs nanowires and nanobelts were synthesised successfully using improved chemical vapor deposition. Based on the InGaAs nanowire, photodetectors were fabricated for the first time. The optoelectric performances of the photodetectors were investigated. The results are as follow:?1? InAs and GaAs powers were used as the source and Au particles were used as catalyst. High quality InGaAs alloy nanowires were synthesized through one step chemical vapor deposition method. XRD measurements indicate that the as-grown nanowires have the cubic zinc blende?ZB? structure. SEM and TEM results show that the as-grown InGaAs nanowires have a length of up to 10 ?m and a diameter of 150 nm. The content of In is higher than that of Ga. EDS results reveal that In concentration, x, being ⁰.65 in our ternary Inx Ga1-x As nanowires.Temperature-dependent photoluminescence spectra of the In_0.65Ga_0.35As nanowires demonstrated that the good optical properties and single crystalline character.?2? Based on the In_0.65Ga_0.35As nanowires, nanowire photodetectors were fabricated using lithography and thermal evaporation. The fabricated devices show excellent light response over a broad spectral range from 1100 to 2100 nm, with a responsivity of 6.5×10³ AW^-1, an external quantum efficiency of 5.04×105%. The responsivity of In_0.65Ga_0.35As is much higher than those of InGaAs quantum and film photodetector. The reason of the high performance of the devices was also been investigated.?3? Based on simple chemical vapor deposition, InAs and GaAs power mixture in the 2:1 weight ratio was used to grow InGaAs alloy nanobelts for the first time. SEM,TEM, EDS and PL measurements were carried out to investigate the structural and optical characterization of the as-grown sample. The results show that the nanobeltswere single crystalline In0.82Ga0.18 As nanobelts. The nanobelt show good optical performance at low temperature. Further, two kinds of nanobelts were also successfully synthesized with different weight ratio and growth temperature. SEM and EDS characterization demonstrate that these nanobelts are InGaAs alloy nanobelts.