TY - JOUR
T1 - Direct observation of dopant atom diffusion in a bulk semiconductor crystal enhanced by a large size mismatch
AU - Ishikawa, Ryo
AU - Mishra, Rohan
AU - Lupini, Andrew R.
AU - Findlay, Scott D.
AU - Taniguchi, Takashi
AU - Pantelides, Sokrates T.
AU - Pennycook, Stephen J.
N1 - Publisher Copyright:
© 2014 American Physical Society.
PY - 2014/10/6
Y1 - 2014/10/6
N2 - Diffusion is one of the fundamental processes that govern the structure, processing, and properties of materials and it plays a crucial role in determining device lifetimes. However, direct observations of diffusion processes have been elusive and limited only to the surfaces of materials. Here we use an aberration-corrected electron microscope to locally excite and directly image the diffusion of single Ce and Mn dopants inside bulk wurtzite-type AlN single crystals, identifying correlated vacancy-dopant and interstitial-dopant kick-out mechanisms. Using a 200 kV electron beam to supply energy, we observe a higher frequency of dopant jumps for the larger and heavier Ce atoms than the smaller Mn atoms. These observations confirm density-functional-theory-based predictions of a decrease in diffusion barrier for large substitutional atoms. The results show that combining depth sensitive microscopy with theoretical calculations represents a new methodology to investigate diffusion mechanisms, not restricted to surface phenomena, but within bulk materials.
AB - Diffusion is one of the fundamental processes that govern the structure, processing, and properties of materials and it plays a crucial role in determining device lifetimes. However, direct observations of diffusion processes have been elusive and limited only to the surfaces of materials. Here we use an aberration-corrected electron microscope to locally excite and directly image the diffusion of single Ce and Mn dopants inside bulk wurtzite-type AlN single crystals, identifying correlated vacancy-dopant and interstitial-dopant kick-out mechanisms. Using a 200 kV electron beam to supply energy, we observe a higher frequency of dopant jumps for the larger and heavier Ce atoms than the smaller Mn atoms. These observations confirm density-functional-theory-based predictions of a decrease in diffusion barrier for large substitutional atoms. The results show that combining depth sensitive microscopy with theoretical calculations represents a new methodology to investigate diffusion mechanisms, not restricted to surface phenomena, but within bulk materials.
UR - http://www.scopus.com/inward/record.url?scp=84907841981&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.113.155501
DO - 10.1103/PhysRevLett.113.155501
M3 - Article
AN - SCOPUS:84907841981
SN - 0031-9007
VL - 113
JO - Physical Review Letters
JF - Physical Review Letters
IS - 15
M1 - 155501
ER -