p-Channel Oxide Thin Film Transistors Using Solution-Processed Copper Oxide

Abstract

Cu2O thin films were synthesized on Si (100) substrate with thermally grown 200-nm SiO2 by sol-gel spin coating method and postannealing under different oxygen partial pressure (0.04, 0.2, and 0.9 Torr). The morphology of Cu2O thin films was improved through N2 postannealing before O2 annealing. Under relatively high oxygen partial pressure of 0.9 Torr, the roughness of synthesized films was increased with the formation of CuO phase. Bottom-gated copper oxide (CuxO) thin film transistors (TFTs) were fabricated via conventional photolithography, and the electrical properties of the fabricated TFTs were measured. The resulting Cu2O TFTs exhibited p-channel operation, and field effect mobility of 0.16 cm2/(V s) and on-to-off drain current ratio of ∼1×10(2) were observed in the TFT device annealed at PO2 of 0.04 Torr. This study presented the potential of the solution-based process of the Cu2O TFT with p-channel characteristics for the first time.

Metal oxide semiconductor thin-film transistors for flexible electronics

“…75,298,299 Moreover, doping of n-type metal oxide semiconductors has enabled the demonstration of p-type TFTs based on P-and N-doped ZnO NW, 259,300 as well Ga 2 O 3 :Zn. 70 Among all the reported p-type metal oxide semiconductor TFTs, [70][71][72][73][74][75]79,[280][281][282][283][284][285][286][287][288][289][290][291][292][293][294]300 only few devices have been fabricated on flexible substrates. 36,79,257,267,272,273,285,289 This is mainly due to the high deposition and annealing temperatures (typically !200 C) that are required, which are incompatible with flexible temperature-sensitive substrates.…”

A review of recent advances in transparent p-type Cu2O-based thin film transistors

“…Many workers have successfully employed the chemical technique to prepare Cu 2 O films where Copper(II) chloride [36], Copper (II) acetate [37][38][39][40] or Copper (II) sulfate [41,42] were used as a starting compound. However, copper (II) acetate is the much preferable starting compound due to the solubility, ease of decomposition and low sensitivity to moisture of the precursor solutions prepared from acetate groups [43,44].…”

“…Lately, using a two-step annealing process to improve surface uniformity, Kim et al [39] presented the potential of using the solution process to fabricate p-type Cu 2 O TFT for the first time. Their transistor exhibited p-channel operation with a field effect mobility of 0.16 cm 2 /V s and on/off drain current ratio of ∼1 Â 10 2 .…”

A Review of Low‐Temperature Solution‐Processed Metal Oxide Thin‐Film Transistors for Flexible Electronics

“…Research in this area has focused mainly on improving the field effect mobility of p‐type oxide semiconductor‐based TFTs. Especially, most of p‐type solution‐processed oxide TFTs show field‐effect mobility, <1 cm 2 V −1 s −1 ( Figure ), which is still very low compared with n‐type solution‐processed oxide TFTs . In general, oxide semiconductors have a high formation energy regarding metal defects that contribute to hole concentration.…”