Kai Shum Group

 Research Projects


OmniPV Corporation

CsSnI3 -- Synthesis, characterization, and applications

In this industry-funded project, we have demonstrated that CsSnI3-based polycrystalline semiconductor thin films can be inexpensively synthesized and have found interesting optical properties from these thin films. Based on this preliminary work, we believe that the perovskite-structured CsSnI3 compound is a potentially useful semiconductor material that, in many respects, is different from common zinc-blende semiconductor materials.

The left figure shows the primitive unit cell for CsSnI3 semiconductor compound, consists of 4 Cs, 4 Sn, and 12 I atoms. Color code: Cs - Green, Sn - Red, and I - Blue.

First Nano

-- A Division of

CVD Equipment Corporation

New York State Foundation for Science, Technology, and Innovation (NYSTAR)

ZnO -- Nanostructures systhesized by chemical vapor deposition (CVD) and their optical properties

We have carried out a study on how high quality ZnO films can be synthesized on silicon and sapphire substrates by CVD method with a solid source. It was not successful to deposit uniform high quality ZnO films on silicon substrates, instead, various high crystal quality nanostructures were epitaxially grown on ZnO pre-seeded silicon substrates. However, we have demonstrated that high quality ZnO films can be grown on sapphire substrates by CVD, encouraging more extensive work to enhance the growth speed.


The left figure shows the photoluminescence spectra from 9 to 350 K from a sample containing a two-dimensionally scattered ZnO nano rods as one of them is shown in the inset of this figure.

Sun Harmonics Ltd.


Cu(InGa)Se2 -- High quality thin-film synthesis and characterization for high efficiency solar cells

Thin-film solar power generation may serve as a paradigm shift toward distributed electricity generation at cost parity with other forms of energy. Cu(InGa)Se2 (CIGS) has long been the most promising thin-film photovoltaic material. Although world-wide intensive efforts, it still lacks of a reliable and cost-effective manufacturing process for high quality CIGS thin-films. This project is to conduct a thorough investigation on various inter-related physical processes that affect the effective manufacturing of high quality CIGS thin-films.

The left figure shows the energy band diagram for a CuInSe2 thin-film solar cell.



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