Impact of Organic Molecule-Induced Charge Transfer on Operating Voltage Control of Both n‑MoS₂ and p‑MoTe₂ Transistors

Since transition metal dichalcogenide (TMD) semiconductors are found as two-dimensional van der Waals materials with a discrete energy bandgap, many TMD based field effect transistors (FETs) are reported as prototype devices. However, overall reports indicate that threshold voltage (Vth) of those FETs are located far away from 0 V whether the channel is p- or n-type. This definitely causes high switching voltage and unintended OFF-state leakage current. Here, a facile way to simultaneously modulate the Vth of both p- and n-channel FETs with TMDs is reported. The deposition of various organic small molecules on the channel results in charge transfer between the organic molecule and TMD channels. Especially, HAT-CN molecule is found to ideally work for both p- and n-channels, shifting their Vth toward 0 V concurrently. As a proof of concept, a complementary metal oxide semiconductor (CMOS) inverter with p-MoTe2 and n-MoS2 channels shows superior voltage gain and minimal power consumption after HAT-CN deposition, compared to its initial performance. When the same TMD FETs of the CMOS structure are integrated into an OLED pixel circuit for ambipolar switching, the circuit with HAT-CN film demonstrates complete ON/OFF switching of OLED pixel, which was not switched off without HAT-CN

Impact of Organic Molecule-Induced Charge Transfer on Operating Voltage Control of Both n‑MoS₂ and p‑MoTe₂ Transistors

Since transition metal dichalcogenide (TMD) semiconductors are found as two-dimensional van der Waals materials with a discrete energy bandgap, many TMD based field effect transistors (FETs) are reported as prototype devices. However, overall reports indicate that threshold voltage (Vth) of those FETs are located far away from 0 V whether the channel is p- or n-type. This definitely causes high switching voltage and unintended OFF-state leakage current. Here, a facile way to simultaneously modulate the Vth of both p- and n-channel FETs with TMDs is reported. The deposition of various organic small molecules on the channel results in charge transfer between the organic molecule and TMD channels. Especially, HAT-CN molecule is found to ideally work for both p- and n-channels, shifting their Vth toward 0 V concurrently. As a proof of concept, a complementary metal oxide semiconductor (CMOS) inverter with p-MoTe2 and n-MoS2 channels shows superior voltage gain and minimal power consumption after HAT-CN deposition, compared to its initial performance. When the same TMD FETs of the CMOS structure are integrated into an OLED pixel circuit for ambipolar switching, the circuit with HAT-CN film demonstrates complete ON/OFF switching of OLED pixel, which was not switched off without HAT-CN

Kaplan-Meier survival curves and comparisons of survival rates by log-rank test.

<p>(A) Mortality rates gradually increased with the increment of age categories (<i>P = </i>0.0000). (B) Females showed better survival rate compared to males (<i>P = </i>0.0004). (C) Survival rate was better for patients without diabetes than that with diabetics (<i>P = </i>0.0000). (D) Patients covered by National Health Insurance experienced higher better survival rate compared to Medical Aid beneficiaries (<i>P = </i>0.0000). (E) Patients on hemodialysis experienced significant survival benefit over patients on peritoneal dialysis in the intention-to-treat analysis (<i>P = </i>0.0000). (F) As the modified Charlson comorbidity index for end-stage renal disease patients increased, survival rates significantly decreased (<i>P = </i>0.0000).</p

Comparision of hazard ratios of all independent predictors for mortality in the multivariate Cox analysis according to the age categories.

<p>Age, peripheral vascular disease, and hemiparesis were the factors by which mortality risk gradually increased with increasing age groups. However, the influences of Medical Aid, peritoneal dialysis, diabetes mellitus, congestive heart failure, liver disease, and any malignancy on the mortality sequentially decreased with aging. * Mortality rates between patients on hemodialysis and those on peritoneal dialysis were compared in the intention-to-treat analysis. HR, hazard ratio; CI, confidence interval.</p

Cumulative survival rate at each 1-year interval^*.

*<p>All data are presented as percent (%).</p><p>ITT, intention-to-treat; AT, as-treated; CCI, Charlson comorbidity index.</p

Baseline characteristics.

*<p>Statistical differences according to age group were calculated in χ² test.</p><p>ITT, intention-to-treat; CCI, Charlson comorbidity index.</p

Results of the Cox proportional hazards analysis for all-cause mortality.

*<p>All-cause mortality was adjusted for all parameters with <0.10 of <i>P</i>-value in the univariate analysis.</p>†<p>Mortality rates between patients on hemodialysis and those on peritoneal dialysis were compared in the intention-to-treat analysis.</p><p>HR, hazard ratio; CI, confidence interval.</p