White-light emissions from p-type porous silicon layers by high-temperature thermal annealing

¹  Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University Tainan 70101, Taiwan, ROC
²  Department of Electronics Engineering, St. John's University - Taipei 25135, Taiwan, ROC
³  Institute of Material Science and manufacturing, Chinese Culture University - Taipei 11114, Taiwan, ROC
⁴  Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University Hsinchu 300, Taiwan, ROC

Corresponding author: jclin@mail.sju.edu.tw

Received: 6 July 2008
Accepted: 11 December 2008

Abstract

In this study, the white-light emissions, including red, green and blue colors, appearing on the same porous silicon samples are originally introduced by a thermal-annealing method. The SEM, FTIR, and PL are discussed for different annealing temperature cases. The FTIR is used to monitor the chemical bonding structures of the PS samples under different annealing temperatures. The results show that the variation of chemical bonding relates to the variation of the emission wavelength. The emission intensities of the blue-green-light components are enhanced with the increase of annealing temperature. The PL spectra cover the entire visible region under the excitations of He-Cd laser beam, and a strong white-light emission can be observed by the naked eye at room temperature.