Physical Review B 72, 115337 (2005)

Từ Thư viện Khoa học VLOS
Bước tới: chuyển hướng, tìm kiếm
Roughness-induced piezoelectric charges in wurtzite group-III-nitride heterostructures
Roughness-induced piezoelectric charges in wurtzite group-III-nitride heterostructures
 Tạp chí Physical Review B 2005 27 September 2005; 72 (11):115337
 Tác giả   Doan Nhat Quanga, Nguyen Huyen Tungb, Vu Ngoc Tuocb, Nguyen Viet Minhb and Pham Nam Phongb
 Nơi thực hiện   a Center for Theoretical Physics, Vietnamese Academy of Science and Technology, P.O. Box 429, Boho, Hanoi 10000, Vietnam

bInstitute of Engineering Physics, Hanoi University of Technology, 1 Dai Co Viet Road, Hanoi, Vietnam

 Từ khóa   piezoelectric, strain relaxation, heterostructures, wurtzite structure
  DOI   URL  PDF

Abstract

We present a theoretical study of the disorder effect due to interface roughness on piezoelectricity in wurtzite group-III-nitride heterostructures, e.g., AlGaN/GaN. We have proved that interface roughness gives rise to random nonuniform fluctuations in the piezoelectric polarization. As a result, besides the uniform density of sheet piezoelectric (and spontaneous) polarization-induced charges on the interface, reported in the existing literature, there must exist fluctuating densities of bulk piezoelectric charges inside of both the strained and relaxed layers as well as a fluctuating density of sheet piezoelectric charges on the interface. The densities of these charges and their electric field were generally found to be high. The maximal rms density of roughness-induced bulk charges may be so large as 10^{{21}}e/cm^{3}, while the rms density of roughness-induced sheet charges may be of the order of magnitude of the uniform density of sheet piezoelectric charges, up to 10^{{13}}e/cm^{2}. Thus, the effects of piezoelectric polarization on the conductivity in actual wurtzite group-III-nitride heterostructures turn out to be counteracting, namely as a source of making up the two-dimensional electron gas, but also as a source of their scattering.