Red-Green-Blue MOSLED Made by PECVD Grown SiO x with Detuning RF Plasma Power
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1208-O07-06
Red-green-blue MOSLED made by PECVD grown SiOx with detuning RF plasma power Chih-Hsien Cheng1, Bo-Han Lai1, and Gong-Ru Lin1 1 Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, No. 1 Roosevelt Road Sec. 4, Taipei 106, Taiwan R.O.C. ABSTRACT Si quantum dot (Si-QD) based multi-color metal oxide semiconductor lighting emission diodes (MOSLEDs) made on Si-rich SiOx grown by detuning RF plasma power in a plasma enhanced chemical vapor deposition (PECVD) system are demonstrated. With the RF plasma powers increasing from 50 to 70 W at 10 W increment, the turn-on voltage and maximum electroluminescence (EL) power red-, green- and blue-color MOSLEDs increase from 70, 90 and 99 V and 7, 26 and 55 nW, respectively. The power-current slope of 0.51, 3.24 and 53.82 mW/A are obtained for these MOSLEDs with corresponding power conversion ratio (PCR) of 5.13×10-6, 2.52×10-5 and 2.47×10-4. Both the turn-on voltage and power slope linearly increase with enhancing thickness of the Si-QD based MOSLED. INTRODUCTION The investigations on nanocrystals or other nanostructures of semiconductors become popular in recent years due to their promising applications in nano-photonics and optoelectronics, especially in the fields of optical interconnect, micro-biophotonic sensing, and full-color display, etc. One intriguing research to attract extensive interests from the viewpoint of device applications is the synthesis of Si quantum dots (Si-QDs) embedded in SiO2 matrix, since the process is compatible with the manufacture of modern integrated circuit based on Si and SiO2, Previously, Linnors and Lalic have analyzed the nearly coincident PL and EL spectra of the n+Si/SiOx/p+-Si MOSLED with Si-QD embedding in the SiOx matrix [1]. Therefore, the Si-QD doped Si-rich SiO2 could be one alternative particularly important for the evolution of visiblelight emitting devices. Chen et al. have observed that the EL peak wavelength from Si-QD embedded SiO2 diode can be shortened to 490 10 nm [2]. Wang et al. also reported that the EL peak was significantly blue-shifted from 780 to 600 nm by decreasing the a-Si:H sub-layer thickness [3]. Jambois et al. found the Si-QD related EL wavelength shift (from 950 to 740 nm) as a function of the bias voltage [4]. Similar trend on EL peak wavelength blue-shifting from 800 to 650 nm after CO2 laser rapid-thermal-annealing was also observed by Lin et al. [5]. Even though, there are few reports emphasized on discussing the shifting EL mechanism for such SiQD based MOSLEDs for broadband-tuning of EL wavelength in visible region. In this work, the fabrication and electrical properties of Si-QD based MOSLED made on thermally annealed PECVD grown SiOx film with the thickness of the SiOx layer precisely controlled at 150 and 350 nm by PECVD system are investigated. Different EL emitting colors can be achieved by properly detuned by changing the RF plasma power during PECVD growth. The performances of MOSLEDs with three EL emitting colors (red, green a
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