Multi-Functional Optoelectronic Heterostructure Devices Based on Transfer Printing of Nanomaterials

Abstract

Heterostructure devices, combining different electronic properties of semiconductors, offer novel electronic functionalities, which are critically required in emerging applications in high performance and multi-functional electronics. Previously, heterostructure devices have attracted a great attention due to the enhancing performances, adding functionalities and broadening absorption range, through components modulation, resulting in many applications in high electron mobility transistors, non-volatile memory, light emitting diodes, and broadband photodetectors. However, traditional semiconductor heterostructures present significant challenges due to the lattice constant mismatch with other substrates and generation of defects during the direct growth and deposition processes. To address these challenges, a transfer printing was introduced to heterogeneously integrate various nanomaterials onto arbitrary substrates, whereby the bonding at heterointerfaces with a large lattice mismatch is facilitated by van der Waals forces during the transfer printing processes. The transfer printing can provide a freedom of material choice, from zero to three dimensional materials, in the formation of heterostructures without the restriction from lattice mismatch, which enabled various heterostructure devices with unique physical properties. In this thesis, we demonstrate multi-functional optoelectronic heterostructure devices based on transfer printing of nanomaterials. First, in chapter 1, we briefly introduce the research trends in electronic devices and basic concept of transfer printing methods and multi-functional heterostructure devices. In chapter 2, we demonstrate a new type of heterostructure device based on black phosphorus and n-InGaAs nanomembrane semiconductors. The device offers gate-tunable rectification and switching behaviors. In addition, the proposed heterojunction diode can be programed by the modulation of forward current due to the capacitive gating effect. Furthermore, the device is photoresponsive in a spectral range spanning the ultraviolet to near infrared. In chapter 3, we describe the fine patterning technique of silver nanowires on various substrates using vacuum filtration and transfer printing process. This technique provides very simple and cost-effective fabrication for fine patterning of AgNWs electrode for optically transparent and mechanically flexible optoelectronic device applications. This patterning technique can be applied to other nanomaterials such as CNT and graphene and combination of nanomaterials to realize highly flexible and transparent optoelectronic devices. In chapter 4, the large-area MoS2 film and pattering process is demonstrated by shadow mask assisted transfer printing process. The liquid exfoliated MoS2 flakes can be easily patterned by vacuum filtration with polyimide shadow mask. Patterned film is transferred to arbitrary substrate by using transfer printing process for high performance and flexible electronic applications. Therefore, the heterostructure devices made by transfer printing are advantageous in scalability and avoids complicated fabrication process for multi-functional applications.