ZnO Heterostructured Light-emitting Diodes by Metal-organic Chemical-vapor Deposition

to be published on :

3^rd MRS-S Conference on Advanced Materials

(Incorporating MRS-S and MRS-I Mumbai-Chapter Joint Indo-Singapore Meeting)

Jointly Organized by

The Materials Research Society of Singapore (MRS-S)

and

The Institute of Materials Research and Engineering (IMRE)

25 – 27 February 2008

IMRE Auditorium, SINGAPORE

S. Iwan,¹ S.T. Tan,² J.L. Zhao,¹and X.W. Sun2

¹ Nanyang Technological University

² Institute of Microelectronics & Nanyang Technological University

This paper reports the ZnO heterostructure light-emitting diodes based on n-ZnO/SiO_x/n-Si and n-ZnO/SiO_x/p-Si. The devices were fabricated by a home-made shower-head injector metal-organic chemical-vapor deposition. From the I-V characteristic, n-ZnO/SiO_x/n-Si shows diodes like rectifying, while ZnO/SiO_x/p-Si shows symmetric nonlinear behavior due to the double Schottky barriers at the interface. n-ZnO/SiO_x/n-Si and n-ZnO/SiO_x/p-Si diodes emit light when a positive bias applied at Si side. Ultraviolet emission at ~390nm with an orange-emission centered at ~600nm were observed in electroluminescence spectra of n-ZnO/SiO_x/n-Si diodes, while whitish emission centered at ~520 nm was observed for n-ZnO/SiO_x/p-Si diodes. Besides, we have realized the epitaxial growth of ZnO (0002) on Si (111) substrate via using the MgO/TiN buffer layers. The obtained n-ZnO/MgO/TiN/n-Si heterostructure was further employed to fabricate LED and strong electroluminescence ranging from 350 to 850nm and centered at ~530nm, was achieved in the device when a positive voltage is applied at Si substrate.