Blue-Green Light Emission from a-SiC_x:H-Based Fabry--Perot Microcavities

A Si-based novel Fabry--Perot microcavity device that can emit blue-green light at room temperature is proposed and fabricated. One of its Bragg reflectors consists of periodically stacked a-SiO₂/a-Si:H layers deposited on the glass by plasma enhanced chemical vapour deposition. The other reflector is a sputtered Al film. The active region between both the reflectors is constructed by a p-type a-SiC_x:H/intrinsic-type a-SiC_x:H junction from which the electroluminescence (EL) is originated. The EL spectra of this device are recorded by RENISHAW RM2000, a sharp and strong EL peak at 483nm with FWHM of 20nm is observed when the device is driven by dc voltages of 8V, 12V and 18V at room temperature. The intensity of EL increases with the applied voltage while the luminescence wavelength keeps unchanged. Compared with the EL spectra from the sample without the Bragg reflector, the luminescence intensity is about 10 times enhanced and the peak is narrowed greatly. The luminescence mechanism is analysed in detail.