Solution-processable integrated CMOS circuits based on colloidal CuInSe2 quantum dots

Hyeong Jin Yun,Jeongkyun Roh,Matt Law,Darren Chi Jin Neo,Victor I Klimov,Jaehoon Lim

doi:10.1038/s41467-020-18932-5

Abstract

The emerging technology of colloidal quantum dot electronics provides an opportunity for combining the advantages of well-understood inorganic semiconductors with the chemical processability of molecular systems. So far, most research on quantum dot electronic devices has focused on materials based on Pb- and Cd chalcogenides. In addition to environmental concerns associated with the presence of toxic metals, these quantum dots are not well suited for applications in CMOS circuits due to difficulties in integrating complementary n- and p-channel transistors in a common quantum dot active layer. Here, we demonstrate that by using heavy-metal-free CuInSe2 quantum dots, we can address the problem of toxicity and simultaneously achieve straightforward integration of complimentary devices to prepare functional CMOS circuits. Specifically, utilizing the same spin-coated layer of CuInSe2 quantum dots, we realize both p- and n-channel transistors and demonstrate well-behaved integrated logic circuits with low switching voltages compatible with standard CMOS electronics.

Highlights

The emerging technology of colloidal quantum dot electronics provides an opportunity for combining the advantages of well-understood inorganic semiconductors with the chemical processability of molecular systems
By varying the halide, we can tune the doping from highly degenerate p-type (Cl−) to nondegenerate p-type (I−) and to ambipolar (Br−), which exploits the effect of surface dipoles on absolute energies of the colloidal quantum dots (CQDs) electronic states
We show that the transport polarity in halide-treated CQD films can be switched to n-type by the incorporation of indium implemented using moderatetemperature annealing of prefabricated field-effect transistors (FETs) with In contacts

Summary

Introduction

The emerging technology of colloidal quantum dot electronics provides an opportunity for combining the advantages of well-understood inorganic semiconductors with the chemical processability of molecular systems. As proof of the practical utility of the developed methodologies for controlling charge transport in CuInSe2 CQD films, we demonstrate well-behaved, low-switching-voltage (0–5 V) CQD-based CMOS devices including an inverter (NOT gate) as well as negative AND (NAND) and negative OR (NOR) logic gates These devices are integrated into the same underlying CQD layer prepared by spin-coating onto a substrate with prepatterned gold and indium electrodes that define, respectively, the complimentary NFETs and PFETs. Importantly, these devices are integrated into the same underlying CQD layer prepared by spin-coating onto a substrate with prepatterned gold and indium electrodes that define, respectively, the complimentary NFETs and PFETs This method does not require patterning of the CQD layer and allows for “programming” the device function at the stage of the deposition of FET contacts and the connecting metal circuits. This should greatly simplify future efforts on device miniaturization and practical implementation of large-scale, highly integrated CMOS circuits

Methods

Results

Conclusion