Fabrication of Micropatterned ZnO Semiconductor Films via Chemical Imprinting

Abstract

Herein, we demonstrated a new patterning method via chemical imprinting with an ammonia-soaked PDMS stamp on the ZnO semiconductor films. The diffused ammonia liquid or gas from the PDMS stamp with fine structures selectively transformed the ZnO films to a water-soluble form (as [Zn(NH3)4-n(OH)n]2-n) at the contact surfaces, and these selectively transformed aqueous salt patterns were dissolved in water. Thus, the array of ZnO micro-patterns were easily fabricated and successfully applied to the active layers of TFTs. In addition, we fabricated the micro-patterns on Li doped ZnO semiconductor films, which have high carrier mobility and low temperature sintering at 300 °C. The present study demonstrates the representative micro-patterned Li doped ZnO TFTs with the field effect mobility of 4.2 cm2·V-1·s-1, on/off current ratio of 8.3 x 107 and low gate leakage current using this chemical imprinting. This patterning method has a good potential for advanced patterning process toward solution-processed ZnO TFTs with high performance

it can be applied to continuous processes at ambient conditions, such as the roll to roll process, and does not require any cumbersome steps.