Browsing by Author "Chen, Hao-Ming"

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Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition
(2017-04-01)
Liao, Yu-Kuang
;
Liu, Yung-Tsung
;
Hsieh, Dan-Hua
;
Shen, Tien-Lin
;
Hsieh, Ming-Yang
Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin filmswith the thickness of a fewnanometers on rough surfaces. We present a new "paradigm shift" non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs) with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD) and chemical bath deposition (CBD) as used by the Cu(In, Ga) Se2 (CIGS) thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase.
Growth and Fabrication of GaN Light Emitting Diode on Patterned-Sapphire Substrate
(2013-01-01)
Binh-Tinh Tran
;
Ming, Chen-Hauw
;
Lin, Kung-Liang
;
Chen, Hao-Ming
;
Wang, Ching-Chian
In this study, the growth of GaN-films-based light emitting diodes (LEDs), have been clearly demonstrated on wet-etching patterned sapphire substrate (PSS) and conventional LEDs. The wet-etching PSS LED device showed a significantly higher performance than the conventional LED device. The wet-etching PSS LED device exhibited a leakage current of 9 mA under a bias of 8 V, an external quantum efficiency and output powers of 35.09 % and 19.23 mW under 20 mA injection current as compared to 12 mA, 27.23%, and 15.02 mW of the conventional LED device.