"Nanocomposites and nanomaterials"

Low temperature magnetotransport properties in GaAs whiskers
Druzhinin A.A., Ostrovskii I.P., Khoverko Yu.M., Liakh-Kaguy N.S., Chemerys D.V.
Lviv Polytechnic National University. Bandery st., 12, Lviv-79013, Ukraine. 
E-mail: dmytro.v.chemerys@lpnu.ua

The nanostructures of A3B5 compound are investigated by researchers due to their wide application, especially compounds based on GaAs are used as photodiodes with high bandwidth [1]. Magnetotransport properties in GaP0.4As0.6 whiskers were studied in our previous work [2]. The negative magnetoresistance effect was revealed and explained due to size effect existence in studied whiskers. Therefore, magnetoresistance behaviour studies of GaAs whiskers at low temperatures and magnetic fields 0-14 T are the aim of the work.
GaAs whiskers were grown by chemical transport reactions method in closed bromide system with the diameter of 20-40 μm. The studied whiskers were doped to concentration in vicinity of the metal-insulated transition (~ 1017 сm-3). The ohmic electrical contacts to GaAs whiskers with Au microwires were created due to the pulse welding method.
The magnetoresistance and temperature dependencies of resistance in GaAs whiskers were studied in the temperature range 4.2-77 K. Changes in the magnetoresistance behavior were found at different temperatures. Both positive and negative magnetoresistances in the field of magnetic fields 0-14 T was found. The nature of the detected positive and negative effects of magnetoresistance in GaAs whiskers and various possible reasons for explaining their behaviour were proposed. The practical application of GaAs whiskers was also proposed as result of the studied low temperature properties.

1.	Xie, S., Zhou, X., Zhang, S., Thomson, D. J., Chen, X., Reed, G. T., ... & Tan, C. H. InGaAs/AlGaAsSb avalanche photodiode with high gain-bandwidth product// Optics express.-2016.-24(21).-P. 4242-24247. 
2.	Druzhinin, A. A., Liakh-Kaguy, N. S., Ostrovskii, I. P., & Khoverko, Y. M. Magnetoresistance of GaP0.4As0.6 Whiskers in Vicinity of MIT// Journal of nano-and electronic physics.-2019.-11, N 4.-P. 04007-1.