Sustained hole inversion layer in a wide-bandgap metal-oxide semiconductor with enhanced tunnel current

Abstract

Wide-bandgap, metal-oxide thin-film transistors have been limited to low-power, n-type electronic applications because of the unipolar nature of these devices. Variations from the n-type field-effect transistor architecture have not been widely investigated as a result of the lack of available p-type wide-bandgap inorganic semiconductors. Here, we present a wide-bandgap metal-oxide n-type semiconductor that is able to sustain a strong p-type inversion layer using a high-dielectric-constant barrier dielectric when sourced with a heterogeneous p-type material. A demonstration of the utility of the inversion layer was also investigated and utilized as the controlling element in a unique tunnelling junction transistor. The resulting electrical performance of this prototype device exhibited among the highest reported current, power and transconductance densities. Further utilization of the p-type inversion layer is critical to unlocking the previously unexplored capability of metal-oxide thin-film transistors, such applications with next-generation display switches, sensors, radio frequency circuits and power converters.

Enhanced photocurrent in organic photodetectors by the tunneling effect of a hafnium oxide thin film as an electron blocking layer

“…However, when the thickness was 5.5 nm, accumulated holes in the active layer owing to the HOMO level of hafnium oxide caused energy band bending, leading to quantum tunneling and extraction of holes to the ITO electrode. 18 The highest on-off current ratio of 1.27 Â 10 5 was observed for the OPD with 5.5 nm of hafnium oxide.…”

“…As shown in Fig. 2, photocurrent density was enhanced by the tunneling effect of hafnium oxide under light exposure owing to energy band bending, which is induced by hole accumulation, 18 and the leakage current from external bias was blocked by the high LUMO level of hafnium oxide. Table 1 and Fig.…”

“…16,17 In addition, hafnium oxide is an effective material for blocking carriers owing to its characteristics as an insulator. In a $5 nm thin lm, tunneling can happen in certain device congurations 18,19 and has been shown to occur in OPD devices.…”

Perspective of zinc oxide based thin film transistors: a comprehensive review

“…Oxide semiconductors TFT have been mainly limited to n-type electronic applications because of the lack of availability of p-type oxide semiconductor. Researchers from the University of Alberta, in 2016, investigated the ZnO semiconductor that is able to sustain a strong p-type inversion layer using ultra-thin high- k dielectric constant barrier when sourced with a p-type material (Shoute et al , 2016). A ZnO film of 25 nm was deposited on a p-type (100) silicon wafer and a 4 nm thick HfO 2 high -k oxide layer was deployed as gate insulator.…”

Modulating Thin Film Transistor Characteristics by Texturing the Gate Metal

“…Shoute et al . implemented TFTs that behaved similar to conventional field effect transistors by sustaining a strong p-type inversion layer in n-type metal oxide TFTs 38 . Cantatore et al .…”