Heteroepitaxial Growth of Nonpolar (1120)-Plane GaN Film via Composite Buffer Layer for the Promising Nonpolar GaN-based Devices | Chapter 3 | Current Innovations in Chemical and Materials Sciences Vol. 5

The development of semipolar/nonpolar structures was lagged behind the development of polar structures. In this study, several nonpolar (1120) a-plane GaN films were grown on semipolar (1102) r-plane sapphire substrates using various buffer layers within a low-pressure metal organic chemical vapor deposition system. The structural properties of nonpolar a-plane GaN films were intensively investigated by the X-ray diffraction and Raman scattering measurements. A set of buffer layers were adopted from a GaN layer to a composite layer containing a multiple AlN layer and an Al composition graded AlGaN layer, the full width at half maximum of the X-ray rocking curves measured along the [0001]- and (1010) -directions of a-plane GaN were reduced by 35% and 37%, respectively. It was also found that an order of magnitude reduction in the basal-plane stacking faults (BSFs) density can be reduced by the heterogeneous interface introduced with the composite buffer layer together. Moreover, the in-plane strains along c- and m-directions were increased from -0.326% and 0.121% to -0.388% and 0.288% when the buffer layer was changed from GaN to AlN, while they were further reduced to -0.107% and 0.137% when the buffer layer was replaced by the composite layer. A BSFs density as low as 2.95×104 cm-1, and a pit-free surface morphology were achieved for the a-plane GaN film grown with the composite buffer layer, which is promising for the development of nonpolar GaN-based devices in the future. This work provides promising insights for the development of nonpolar GaN-based LEDs with high-bandwidth for optical communications and microdisplays in the future.

Author(s) Details:

Jianguo Zhao,
School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.

Boyan Suo,
School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.

Ru Xu,
School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.

Tao Tao,
School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.

Zhe Zhuang,
School of integrated Circuits, Nanjing University, Suzhou, 215163, China.

Bin Liu,
School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.

Xiong Zhang,
Advanced Photonics Center, Southeast University, Nanjing 210096, China.

Jianhua Chang,
School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.

Please see the link here: https://stm.bookpi.org/CICMS-V5/article/view/13128