Li5AlO4 dielectric for low voltage transistor: Its application in metal oxide/quantum dot heterojunction phototransistors.

A solution-processed high-performance subvolt (<1 V) tin oxide (SnO2) thin film transistor (TFT) has been fabricated onto an ion-conducting Li–Al2O3 gate dielectric by utilizing a high-permittivity Mn2O3 gate interface. A comparative device characterization of two different TFTs with and without a Mn2O3 gate interface with an ionic dielectric ensures that n-type Mn2O3 induces an additional electron to the semiconductor/dielectric interface trap states. Consequently, the TFT with a Mn2O3 interface achieves a lower subthreshold swing (SS) by keeping the threshold voltage closer to zero compared to the TFT without the Mn2O3 gate interface. This SnO2 TFT with Mn2O3 interface requires only 0.6 V to saturate the drain current, and device performance under such low-voltage (0.6 V) operation exhibits an electron mobility of 17 cm2/V·s with on/off ratio of 3.3 × 104 and subthreshold swing of 124 mV/dec. This work provides a potential approach to achieve a high-performance low-voltage TFT by selecting a suitable combination of dielectric materials.

High-performance solution-processed one-volt metal-oxide thin-film transistor (TFT) has been fabricated onto highly p-doped silicon (p++-Si) substrate with sol–gel-derived ion-conducting gate dielectric by using electron-donating TiO2 gate interface. A comparative electrical characterization of two different TFTs with TiO2 and Al2O3 gate interface device reveals that n-type TiO2 works as an electron donor to the semiconductor/dielectric interface trap state. As a consequence, subthreshold swing (SS) of the TiO2 interface device reduces significantly by keeping threshold voltage closer to zero enabling to achieve significantly higher-performance one-volt TFT with respect to “without TiO2” and “with Al2O3” interface devices. Additionally, depleted layer of p++-Si­(111)/TiO2 interface reduces gate leakage current significantly that helps to improve the on/off ratio of the device. Specifically, in this report, one-volt TFT with indium zinc oxide semiconductor has been fabricated by using Li5AlO4 dielectric with TiO2 gate interface that achieved electron mobility of 32 cm2/(V·s) with on/off ratio of 5 × 105 and subthreshold swing of 110 mV/dec. This investigation provides a feasible direction toward the development of high-performance, low-voltage TFT fabrication with various materials combination.

No abstract