Browsing by Author "Huang, Pin-Ruei"

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Boron-doping effect on the super-high density Si quantum dot thin films utilizing a gradient Si-rich oxide multilayer structure
(2019-05-01)
Huang, Pin-Ruei
;
Chen, You-Cheng
;
Kuo, Kuang-Yang
;
Lee, Po-Tsung
;
光電工程學系
Boron (B)-doped gradient Si-rich oxide multilayer (GSRO-ML) structure is utilized to realize super-high density Si quantum dots (QDs) thin films with large carrier tunneling probability by co-sputtering. The B-doping effect on crystalline, optical, electrical and photovoltaic (PV) properties of Si QD thin films is investigated in this study. With increased B-doping concentration, the preserved high crystallinity of Si QDs and the reduced optical bandgap are observed. An optimized doping condition is found for the electrical and PV properties. Further increasing the doping concentration leads to increased inactive B atoms and interfacial over-diffusion. The issue of interfacial over-diffusion can be efficiently improved by inserting lowly B-doped GSRO-ML thin films. Our results show the feasibility and great potential for high efficiency Si-based solar cells integrating Si QDs by properly doped B atoms in GSRO-ML thin film structure.
Enhancement on Photovoltaic Properties of Boron-doped Super-high Density Si Quantum Dot Thin Film
(2014)
Huang, Pin-Ruei
;
Chen, You-Jeng
;
Chang, Jia-Ruei
;
Kuo, Kuang-Yang
;
Lee, Po-Tsung
Boron-doped super-high density nano-crystalline Si quantum dot thin film is demonstrated by utilizing a gradient Si-rich oxide multilayer structure. The boron doping effect and its significant influence on photovoltaic properties are observed and discussed.
Improvement of optical transmittance and electrical properties for the Si quantum dot-embedded ZnO thin film
(2013-10-23)
Kuo, Kuang-Yang
;
Liu, Chuan-Cheng
;
Huang, Pin-Ruei
;
Hsu, Shu-Wei
;
Chuang, Wen-Ling
A Si quantum dot (QD)-embedded ZnO thin film is successfully fabricated on a p-type Si substrate using a ZnO/Si multilayer structure. Its optical transmittance is largely improved when increasing the annealing temperature, owing to the phase transformation from amorphous to nanocrystalline Si QDs embedded in the ZnO matrix. The sample annealed at 700A degrees C exhibits not only high optical transmittance in the long-wavelength range but also better electrical properties including low resistivity, small turn-on voltage, and high rectification ratio. By using ZnO as the QDs' matrix, the carrier transport is dominated by the multistep tunneling mechanism, the same as in a n-ZnO/p-Si heterojunction diode, which clearly differs from that using the traditional matrix materials. Hence, the carriers transport mainly in the ZnO matrix, not through the Si QDs. The unusual transport mechanism using ZnO as matrix promises the great potential for optoelectronic devices integrating Si QDs.
Optical properties and sub-bandgap formation of nano-crystalline Si quantum dots embedded ZnO thin film
(2012-05-07)
Kuo, Kuang-Yang
;
Hsu, Shu-Wei
;
Huang, Pin-Ruei
;
Chuang, Wen-Ling
;
Liu, Chuan-Cheng
In this study, we fabricate ZnO thin films with nano-crystalline Si (nc-Si) quantum dots (QDs) using a ZnO/Si multilayer deposition structure and a post-annealing process, and the formation of high crystallinity of Si QDs embedded in the crystalline ZnO matrix is demonstrated. For optical properties, the essential features of ZnO material, high transmission in long-wavelength and high absorption in short-wavelength ranges, are preserved. We observe significantly enhanced light absorption and an unusual photoluminescence emission peak contributed from the nc-Si QDs in the middle-wavelength range. In addition, we confirm the formation of optical sub-bandgap and the obtained value is quite close to the unusual PL emission peak. We show that meaningful sub-bandgap can form in ZnO thin film by embedding nc-Si QDs while maintaining the advantageous properties of ZnO matrix. This newly developed composite material, nc-Si QD embedded ZnO thin films, can be useful for various electro-optical applications. (C)2012 Optical Society of America
Super-high density Si quantum dot thin film utilizing a gradient Si-rich oxide multilayer structure
(2013-05-17)
Kuo, Kuang-Yang
;
Huang, Pin-Ruei
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
A gradient Si-rich oxide multilayer (GSRO-ML) deposition structure is proposed to achieve super-high density Si quantum dot (QD) thin film formation while preserving QD size controllability for better photovoltaic properties. Our results indicate that the Si QD thin film using a GSRO-ML structure can efficiently increase the QD density and control the QD size. Its optical properties clearly promise the capability of effective bandgap engineering even though these QDs are closely formed. The Si QD thin film using a GSRO-ML structure obviously reveals better electro-optical properties than those using a [silicon dioxide/silicon-rich oxide] multilayer ([SiO2/SRO]-ML) structure owing to the better optical absorption and carrier transport properties. Therefore, we successfully demonstrate that our proposed GSRO-ML structure has great potential for application in solar cells integrating Si QD thin films.