Growth and characterization of Ga doped ZnSnAs 2 thin films on InP substrates

• Published in: Physica status solidi. C Vol. 12; no. 6; pp. 512 - 515
• Main Authors: Kato, Takahiro, Uchiyama, Takashi, Toyota, Hideyuki, Uchitomi, Naotaka
• Format: Journal Article
• Language: English
• Published: 01.06.2015
• ISSN: 1862-6351; 1610-1642
• DOI: 10.1002/pssc.201400295

Abstract We have grown Ga doped ZnSnAs 2 thin films on InP substrates using all‐solid source MBE technique. Using the optimum substrate temperature of 340 ºC and Zn:Sn:As 4 beam equivalent pressure ratio (BEPR) of 24:1:52, samples were prepared with different Ga concentration achieved by changing the Ga flux. Compositional analysis was performed using electron microprobe microanalysis (EMPA). We found that Ga concentration on the cation sites is 20.9% and 8.7%. XRD patterns of Ga doped samples showed only assignable to ZnSnAs 2 :Ga and InP substrate. The lattice constant decreases linearly from 0.5862 to 0.5829 nm with decreasing Ga concentration. The observed concentration dependence indicates that the lattice constant of the thin films can be controlled by Ga doping concentration. Hall coefficient and resistivity of Ga 8.7% doped sample can be well explained by the impurity band model. We were able to resolve the experimentally obtained carrier concentration p exp and mobility μ exp into valence band carrier concentration p v with mobility μ v and acceptor band carrier concentration p a with mobility μ a . The computed apparent values p app and μ app are in good agreement with p exp and μ exp , respectively. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)