We grow complex oxide thin films on 2D materials via remote epitaxy technique. By doing so, high quality thin film membranes can be grown and easily transferred to foreign substrate without damage. The transferred complex oxide membranes can be utilized in various fields including electronics, ferroelectronics, spintronics, or optics.

We develop growth method for high quality, single crystalline 2D materials, such as MoS2 or WSe2, at low temperature using confined growth template. Owing to the low growth temperature, effieicnt 2D electronic deivces like transistors can be fabricated as well as stacked devices.

3D stacking of micro-LEDs and photodetectors for various applications are being researched. Stacking of high efficiency micro-LEDs for higher PPI and reduced pixel area can be achieved. By stacking PD and micro-LED, optical probe with extremely small feature size can be achieved.

We develop a novel method for fabrication of micro-LEDs using sapphire nano-membrane template. With this technique, high efficiency micro-LEDs with low defect density could be obtained without damaging the chip. Moreover, using the sapphire nano-membrane template, size and shape of the micro-LED chips could be easily changed depending on the applications. Our findings would be a key technology for commercializing micro-LED display.

III-V compound semiconductors have been widely used for light-emitting diodes. Nanorod LED, consist of non-polar m-plane GaN, is a promising candidate for next generation optoelectronic device. Nanorod core-shell LEDs reduce piezoelectric polarization in InGaN MQW, which enables high In doping. Therefore, GaN based device with wide range of emission wavelengths can be fabricated. External quantum efficiency (EQE) is increased due to large surface to volume ratio in MQW. 

We develop visible light activated chemoresistive gas sensor based on 2D materials and metal oxide nanoparticles. Visible light illumination enables stable room temperature gas sensing and substantially enhances gas sensing performance. Visible light driven chemoresistive gas sensor is anticipated to be further applied in electric nose.