TY - JOUR
T1 - Polar-charge-induced self-assembly
T2 - Electric effect that causes nonisotropic nanorod growth in wurtzite semiconductors
AU - Turkulets, Yury
AU - Shalish, Ilan
N1 - Funding Information:
Acknowledgments. We gratefully acknowledge the support of a United States—Israel Binational Science Foundation (BSF) Grant No. 2015700. The work was carried out as part of a BSF-NSF collaborative grant (NSF Grant No. ECCS-1610362).
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/3/18
Y1 - 2019/3/18
N2 - Crystals grow by gathering and bonding of atoms to form an ordered structure. Typically, the growth is equally probable in all crystalline directions, but sometimes it is not, as is the case of nanowire growth. Nanowire growth is explained, in most cases, by the presence of liquid metal droplets that mediate between an incoming flux of atoms and a substrate or an existing crystal nucleus, while defining the lateral dimension. Here, we report and explain a mode of nonisotropic crystal growth observed in two wurtzite semiconductors, InN and ZnO. Being of polar structure, wurtzite crystals possess a built-in internal electric field. Thermally excited charges screen the built-in electric field during growth in a nonuniform, yet symmetric, manner, causing the formation of symmetric domains of inverted polarity. These domains limit the lateral expansion of the crystal, inducing a fiber growth mode. The mechanism described here elucidates phenomena in the growth of group III nitrides on sapphire, emphasizing the need to consider the effects of built-in electric fields in the growth of polar semiconductors.
AB - Crystals grow by gathering and bonding of atoms to form an ordered structure. Typically, the growth is equally probable in all crystalline directions, but sometimes it is not, as is the case of nanowire growth. Nanowire growth is explained, in most cases, by the presence of liquid metal droplets that mediate between an incoming flux of atoms and a substrate or an existing crystal nucleus, while defining the lateral dimension. Here, we report and explain a mode of nonisotropic crystal growth observed in two wurtzite semiconductors, InN and ZnO. Being of polar structure, wurtzite crystals possess a built-in internal electric field. Thermally excited charges screen the built-in electric field during growth in a nonuniform, yet symmetric, manner, causing the formation of symmetric domains of inverted polarity. These domains limit the lateral expansion of the crystal, inducing a fiber growth mode. The mechanism described here elucidates phenomena in the growth of group III nitrides on sapphire, emphasizing the need to consider the effects of built-in electric fields in the growth of polar semiconductors.
UR - http://www.scopus.com/inward/record.url?scp=85063544385&partnerID=8YFLogxK
U2 - 10.1103/PhysRevMaterials.3.033403
DO - 10.1103/PhysRevMaterials.3.033403
M3 - Article
AN - SCOPUS:85063544385
VL - 3
JO - Physical Review Materials
JF - Physical Review Materials
SN - 2475-9953
IS - 3
M1 - 033403
ER -