Pixel-less and Pixel-lated Inorganic/Organic Hybrid Infrared Imaging Upconversion Devices
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Date
2013-01-23T14:48:30Z
Authors
Tao, Jianchen
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Nowadays, the industrial standard for infrared imaging systems is to interconnect an infrared photodetector array with a silicon-based read-out-integrated circuit pixel by pixel through existing indium bumping technology for infrared scene detection and then the signal is output optically through a LCD or other imaging devices. Motivated by the high-cost and low-resolution of such configurations, technology that up-converts infrared light to visible light and in particular, an inorganic/organic hybrid imaging upconverter has been developed. The end goal was to provide a high-efficiency and high-resolution alternative for infrared imaging. The inorganic/organic hybrid architecture takes advantage of both the high quantum efficiency of photo-detection for inorganic semiconductors, and the low-cost processing and the topologically perfect structure of organic semiconductors that does not require lattice matching for materials. Based on previous single-element hybrid infrared upconverter designs, both pixel-less and pixel-lated hybrid infrared imaging devices are presented, with experimental results, in this thesis. The pixel-less hybrid infrared imaging upconverter suppresses the lateral carrier diffusion by using a hybrid Schottky junction with an intrinsic interconnection layer between the inorganic and organic parts. The device was fabricated in one large-area mesa and proved that the emitting light spatially correlated with the infrared imaging shone at its back. This device is the first-ever hybrid pixel-less infrared upconverter to successfully demonstrate the imaging of infrared patterns. In contrast, the pixel-lated device consisted of 128 by 128 pixels, and each pixel was an individually working infrared upconverter that integrated a heterojunction phototransistor (HPT) and an organic light emitting diode (OLED). The HPT provides not only the photoresponse upon incoming infrared light but also an amplification of the photocurrent. The pixel-lated device also successfully demonstrated the first-ever upconversion of infrared light, up-converting a light with a wavelength of 1.5 μm to 520 nm.
Description
Keywords
Semiconductor, Upconversion, Imaging, Infrared, Pixel-less, Pixel-lated, Hybrid, Organic, Inorganic