A prospective study of birth weight and prostate cancer risk and mortality in the Health Professionals Follow-up Study.

BACKGROUND: Previous studies have observed inconsistent associations between birth weight and aggressive prostate cancer risk. This study aimed to prospectively analyse this association in the Health Professionals Follow-up Study (HPFS). METHODS: Birth weight was self-reported in 1994, and prostate cancer diagnoses were assessed biennially through January 2017 and confirmed by medical record review. Multivariable Cox proportional hazards regression was used to evaluate the association between birth weight and prostate cancer risk and mortality. RESULTS: Among 19,889 eligible men, 2520 were diagnosed with prostate cancer, including 643 with higher-grade/advanced stage, 296 with lethal, and 248 with fatal disease. Overall, no association was observed for increasing birth weight with risk of overall prostate cancer, lower-grade, and organ-confined disease. However, a borderline statistically significant positive trend was observed for increasing birth weight with risk of higher-grade and/or advanced-stage prostate cancer (adjusted hazard ratio [HRadj] per pound: 1.05; 95% confidence interval [CI]: 0.99-1.11; P-trend = 0.08), but no associations were observed with risk of lethal or fatal disease (HRadj: 0.99, 95% CI: 0.91-1.08; P-trend = 0.83; and HRadj: 0.99, 95% CI: 0.90-1.08; P-trend = 0.82, respectively). CONCLUSION: No consistent associations were observed between birth weight and prostate cancer risk or mortality in this 22-year prospective cohort study.

Balance and vestibular function and survival in US cancer survivors.

BACKGROUND: Cancer and its treatment damage the musculoskeletal system and induce neurotoxicity, affecting the key sensory inputs for maintaining balance. The present study describes the pattern of balance impairment and evaluated its association with mortality among US cancer survivors. METHODS: Data on a nationally representative sample of cancer survivors from the US National Health and Nutrition Examination Survey from 1999 to 2015 was analyzed. Sensory-specific balance impairment was measured at baseline by the modified Romberg test of standing balance on firm and compliant support surfaces. The linked mortality data were updated through December 31, 2015. RESULTS: Among 511 cancer survivors, 282 (48.3%) had a balance impairment, predominantly attributing to vestibular dysfunction (251; 89.0% of 282 and 44.5% of 511). A higher prevalence of balance impairment was observed among cancer survivors with advanced age, lower socioeconomic status or educational attainment, body mass index <25 kg/m2 , and an inactive lifestyle. During up to 16.4 years of follow-up (median, 11.3 years; 5088 person-years), 253 cancer survivors had died. Cancer survivors with a balance impairment had a 63% higher risk of death from all causes (hazard ratio, 1.63; 95% confidence interval [CI], 1.12-2.38) after adjusting for sociodemographic factors, comorbidities, and cancer type. Specifically, those with vestibular dysfunctions had approximately 1.54 (95% CI, 1.05-2.27) times the risk of death compared to those without any balance impairment. These associations were stronger in males than in females. CONCLUSIONS: In a US nationally representative sample of cancer survivors, balance impairment and vestibular dysfunctions were prevalent and associated with heightened all-cause mortality.

Regular Coffee Consumption Is Associated with Lower Regional Adiposity Measured by DXA among US Women.

BACKGROUND: Coffee is among the most popular daily beverages in the United States. Importantly, coffee consumption has been associated with a lower risk of multiple health outcomes including a reduction in adiposity. DXA is a means to assess body fat and distribution. OBJECTIVES: The aim of this study was to examine the relation between coffee consumption and DXA-assessed adiposity and adiposity distribution. METHODS: Cross-sectional data from the NHANES were used. Participants were adults aged 20-69 y from the 2003-2004 and 2005-2006 waves. Information on coffee consumption was assessed through the FFQ (categorized as no coffee, 0 to <0.25 cup/d, 0.25 to <1 cup/d, 1 cup/d, 2-3 cups/d, or ≥4 cups/d). Both caffeinated and decaffeinated coffee consumption were included. Trunk fat and total fat percentage were measured via whole-body DXA scans. The association between coffee consumption and body fat was investigated using age-adjusted and multivariable-adjusted linear regression models which accounted for sample weights. RESULTS: Higher coffee consumption was associated with significantly lower total body fat percentage and trunk body fat percentage in a dose-response manner (all P values < 0.05) among women. Although this dose-response relation was nonsignificant among men, men aged 20-44 y who drank 2-3 cups/d had 1.3% (95% CI: -2.7%, 0.1%) less total fat and 1.8% (95% CI: -3.3%, -0.4%) less trunk fat than those who did not consume coffee. Furthermore, the association between coffee consumption and body fat percentage exhibited for both caffeinated and decaffeinated coffee among women (all P for trend < 0.001) but not among men (all P for trend > 0.05). CONCLUSIONS: The present study found a significant association between higher coffee consumption and lower DXA-measured adiposity. Moreover, a gender difference in this association in the general US adult population was also observed.

Trends in Sexual Activity and Associations With All-Cause and Cause-Specific Mortality Among US Adults.

BACKGROUND: Sexual activity can be referred to as a health behavior and may also act as an indicator of health status. AIM: To evaluate temporal trends in sexual activity and to examine associations of sexual activity with all-cause and cause-specific mortality risk. METHODS: We examined the trends and prevalence of sexual activity and association of sexual activity with all-cause and cause-specific mortality in a nationally representative sample using data from the US National Health and Nutrition Examination Survey from 2005 to 2016 and the National Health and Nutrition Examination Survey 2005-2014 Linked Mortality File (through December 31, 2015). OUTCOMES: All-cause, cardiovascular disease, and cancer mortality. RESULTS: A total of 15,269 US adults (mean age, 39.1 years [standard error, 0.18 years]) were included in the trend analysis. In the 2015-2016 cycle, while 71.7% (95% CI, 67.7-75.7%) US adults aged 20-59 years engaged in sexual activity ≥ 12 times/year (monthly), only 36.1% (95% CI, 31.6-40.7%) of them engaged in sexual activity ≥ 52 times/year (weekly). Since the 2005-2006 cycle, the estimated prevalence of sexual activity, ≥52 times/year and ≥12 times/year, were both stable over time among overall and each age group (all P for trend >0.1). During a median follow-up of 5.7 years (range, 1-11 years) and 71,960 person-years of observation, among 12,598 participants with eligible information on mortality status, 228 deaths occurred, including 29 associated with cardiovascular disease and 62 associated with cancer. Overall, participants with higher sexual activity frequency were at a lower risk of all-cause death in a dose-response manner (P for trend = 0.020) during the follow-up period. In addition, the multivariable-adjusted hazard ratios for all-cause mortality, CVD mortality, cancer mortality, and other cause mortality among participants who had sex ≥52 times/year compared with those having sex 0-1 time/year were 0.51 (95% CI, 0.34 to 0.76), 0.79 (95% CI, 0.19 to 3.21), 0.31 (95% CI, 0.11 to 0.84), and 0.52 (95% CI, 0.28 to 0.96), respectively. CLINICAL IMPLICATIONS: Sexual activity appears to be a health indicator of all-cause and cancer mortality in US middle-aged adults. STRENGTHS & LIMITATIONS: Clear strengths of the present study include the large representative sample of the noninstitutionalized US population as well as the identification of precise estimates in relation to sexual activity and mortality. However, because of the observational nature of the study design, causality could not be determined. CONCLUSIONS: Sexual activity was found to be associated with a lower risk of mortality from all cause and cancer. Cao C, Yang L, Xu T, et al. Trends in Sexual Activity and Associations With All-Cause and Cause-Specific Mortality Among US Adults. J Sex Med 2020;17:1903-1913.

Handgrip strength is associated with suicidal thoughts in men: Cross-sectional analyses from NHANES.

OBJECTIVE: To investigate the association between handgrip strength and suicidal thoughts in a representative sample of the US adult population using data from the National Health and Nutrition Examination Survey (NHANES). POPULATION AND METHODS: Data from two waves of NHANES (2011-2014) were aggregated. Handgrip strength in kilogram (kg) was defined as the maximum value from the dominant hand. Suicidal thoughts were assessed using one question "Over the last 2 weeks, how often have you been bothered by the following problem: Thoughts that you would be better off dead or of hurting yourself in some way?" and dichotomized to no (not at all) and yes (several days/ more than half the days/ nearly every day). Sex-specific logistic regressions were carried out to analyze associations between handgrip strength and suicidal thoughts. RESULTS: Data on total of 8903 adults (mean age 47.4 ± 0.4 years) were analyzed. Each 5kg increase in handgrip strength was associated with a 16% reduced odds of having suicidal thoughts (0.84, 95% CI: 0.74-0.95) among the overall male population. These associations were stronger in male aged 20-39 years (0.83, 95% CI: 0.70-0.98), and 40-64 years (0.73, 95% CI: 0.63-0.85). In contrast, no associations were observed in females of all age groups. CONCLUSIONS: Males younger than 65 years old with low handgrip strength are significantly more likely to have suicidal thoughts demonstrating a dose-response relationship. Future research is required to confirm/refute our findings and establish if strength interventions can reduce suicidal thoughts.

Disparities in incidence and survival for patients with Ewing sarcoma in Florida.

BACKGROUND: Ewing sarcoma (ES) is a malignant bone tumor most commonly affecting non-Hispanic White (NHW) adolescent males, though recognition among Hispanic individuals is rising. Prior population-based studies in the United States (US), utilizing Surveillance, Epidemiology, and End Results (SEER) have shown higher all-cause mortality among White Hispanics, Blacks, and those of low socioeconomic status (SES). Florida is not part of SEER but is home to unique Hispanic populations including Cubans, Puerto Ricans, South Americans that contrasts with the Mexican Hispanic majority in other US states. This study aimed to assess racial/ethnic disparities on incidence and survival outcomes among this diverse Florida patient population. METHODOLOGY: Our study examined all patients diagnosed with osseous ES (2005-2018) in Florida (n = 411) based on the state's population-based cancer registry dataset. Florida Age-adjusted Incidence Rates (AAIRs) were computed by sex and race-ethnicity and compared to the equivalent populations in SEER. Cause-specific survival disparities among Florida patients were examined using Kaplan-Meier analysis. Univariable and multivariable analyses using Cox regression were performed for race/ethnicity, with adjustment for age, sex, year of diagnosis, site of disease, staging, SES, and insurance type. RESULTS: There was a significantly higher incidence of osseous ES in Florida Hispanic males (AAIR 2.6/1,000,000); (95% CI: 2.0-3.2 per 1,000,000; n = 84) compared to the SEER Hispanic males (AAIR 1.2/1,000,000;1.1-1.4 per 1,000,000; n = 382). Older age, distant metastasis, lack of chemotherapy or surgical resection were statistically significant determinants of poor survival while SES, insurance status and race-ethnicity were not. However, among nonmetastatic ES, Florida Hispanics had an increased risk of death compared to Florida NHW (adjusted Hazard Ratio 2.32; 95%CI: 1.20-4.46; p = 0.012). CONCLUSIONS: Florida Hispanic males have a higher-than-expected incidence of osseous ES compared to the US. Hispanics of both sexes show remarkably worse survival for nonmetastatic disease compared to NHW. This disparity is likely multifactorial and requires further in-depth studies.

Assessing racial/ethnic and nativity disparities in US cancer mortality using a new integrated platform.

BACKGROUND: Foreign-born (FB) populations in the US have significantly increased, yet cancer trends remain unexplored. Survey-based Population-Adjusted Rate Calculator (SPARC) is a new tool for evaluating nativity differences in cancer mortality. METHODS: Using SPARC, we calculated 3-year (2016-2018) age-adjusted mortality rates (AAMRs) and rate ratios (RRs) for common cancers by sex, age group, race/ethnicity, and nativity. Trends by nativity were examined for the first time for 2006-2018. Traditional cancer statistics draw populations from decennial censuses. However, nativity-stratified populations are from the American Community Surveys, thus involve sampling errors. To rectify this, SPARC employed bias-corrected estimators. Death counts came from the National Vital Statistics System. RESULTS: AAMRs were higher among US-born (UB) populations across nearly all cancer types, with the largest UB- FB difference observed in lung cancer among Black females (RR = 3.67, 95%CI = 3.37-4.00). The well-documented White-Black differences in breast cancer mortality existed mainly among UB women. For all cancers combined, descending trends were more accelerated for the UB compared to the FB in all race/ethnicity groups with changes ranging from -2.6% per year in UB Black males to stable (non-significant) among FB Black females. Pancreas and liver cancers were exceptions with increasing, stable, or decreasing trends depending on nativity and race/ethnicity. Notably, FB Black males and FB Hispanic males did not show a favorable decline in colorectal cancer mortality. CONCLUSIONS: While all groups show beneficial cancer mortality trends, those with higher rates in 2006 have experienced sharper declines. Persistent disparities between the UB and the FB, especially among Black people, necessitate further investigation.

Trends and Disparities in Curative-Intent Treatment for Early-Stage Non-Small Cell Lung Cancer: A Population-Based Analysis of Surgery and SBRT.

BACKGROUND: Despite the increasing adoption of stereotactic body radiotherapy (SBRT) as a recommended alternative for early-stage non-small cell lung cancer (NSCLC), population-based research on racial/ethnic disparities in curative-intent treatment accounting for SBRT remains limited. This study investigated trends and disparities in receiving curative-intent surgery and/or SBRT in a diverse, retrospective cohort. METHODS: Early-stage NSCLC cases (2005-2017) from the Florida cancer registry were linked to individual-level statewide discharge data containing comorbidities and specific treatment information. Joinpoint regression assessed trends in treatment receipt. Multivariable logistic regression examined associations between race/ethnicity and treatment type. RESULTS: Among 64,999 patients with early-stage NSCLC, 71.6% received curative-intent treatment (surgery and/or SBRT): 73.1%, 72.4%, and 60.3% among Hispanic, White, and Black patients, respectively (P < 0.01). SBRT use increased steeply from 2005 to 2007 and then by 7.9% annually from 2007 to 2017 (P < 0.01); curative-intent surgery remained stable from 2005 to 2014 before declining by 6.2% annually during 2014-2017 (P = 0.04). The Black-White disparity in receipt of curative-intent treatment was significant [ORadj, 0.65; 95% confidence interval (CI), 0.60-0.71]. Patients with Charlson comorbidity index (CCI)≥3 had 36% (ORadj, 0.64; 95% CI, 0.60-0.69) lower odds of receiving curative-intent surgery and no significant difference for SBRT (ORadj, 1.06; 95% CI, 0.93-1.20) compared with CCI = 0. CONCLUSIONS: Racial disparities in receiving curative-intent treatment for early-stage NSCLC persist despite the availability of SBRT, suggesting the full potential of curative-intent treatment for early-stage NSCLC remains unachieved. IMPACT: Addressing disparities in early-stage NSCLC requires addressing differential treatment patterns and enhancing accessibility to treatments like underutilized SBRT, particularly for high-comorbidity populations such as Black patients.

Elevated breast cancer mortality among highly educated Asian American women.

BACKGROUND: Postmenopausal breast cancer (PMBC) is the most commonly diagnosed and the second leading cause of cancer death among women in the US. Research examining the association between PMBC and education level has been inconsistent; no study in the US has examined how educational level impacts PMBC mortality in Asian American women, a largely immigrant population with above-average educational attainment. METHODS: California Vital Statistics data from 2012-2017 were analyzed to derive age-adjusted mortality rate ratios (MRRs) by education level (associates degree or above referred to as "higher education", high school, less than high school) and race [Non-Hispanic White (NHW), Asian/Pacific Islander (Asian), and its two largest subpopulations: Chinese and Filipino] from negative binomial regression models. RESULTS: PMBC mortality for both NHWs and Asians was greater among women with higher education compared to those who did not complete high school: NHWs had 22% higher PMBC mortality (MRR 1.22; 95% CI: 1.14-1.31) and Asians had 2.6 times greater PMBC mortality (MRR 2.64; 95% CI: 2.32-3.00) than their counterparts who did not complete high school. Asians in the lowest education level had 70% lower mortality than NHWs (MRR 0.30; 95% CI: 0.27-0.34). This mortality advantage among Asians was greatly reduced to only 27% lower among the highest educated (MRR 0.73; 95% CI: 0.68-0.78). For higher educated Filipina women, no mortality advantage was evident compared to NHWs (MRR 0.96; 95% CI: 0.88-1.05). CONCLUSION: PMBC mortality for higher educated Asian women is elevated in comparison to their counterparts with less education. Given that PMBC survival is greater among those with higher education, our findings strongly suggest an excess in the incidence of PMBC (more than double) among higher educated Asian women; this warrants more research into potentially modifiable causes of PMBC in this burgeoning population.

Diet quality, school attendance, and body weight status in adolescent girls in rural Guatemala.

A cluster of factors affects nutritional status among adolescent girls in low- and middle-income countries (LMICs). We investigated the association between school attendance and diet quality among 498 rural adolescent girls (352 attending and 146 not attending school) in Tecpán, Guatemala. In a cross-sectional study, we collected sociodemographic and anthropometric data and characterized the dietary intake using a Food Frequency Questionnaire. We then calculated diet quality using the Healthy Eating Score (HES). Multiple linear regression models were conducted to evaluate the effects of school attendance on diet quality. We found that the overall diet quality among the study participants was poor, according to the HES. However, those who attended school had significantly higher intakes of vitamin A-rich fruits and vegetables (P = 0.04), other fruits (P = 0.01), and milk and milk products (P = 0.004), but a higher intake of fast foods, chips, and saturated fatty acids (P < 0.001). Furthermore, the effects of school attendance on diet quality were significant after adjusting for sociodemographic and lifestyle factors (ß coefficient = -1.70, 95% CI: -3.30 to -0.11) but was attenuated when further adjusted for weight status (ß coefficient = -1.58, 95% CI: -3.17 to 0.02). Our findings suggest that diet quality among girls in rural Guatemala is poor, particularly among those who do not attend school. To advance our understanding of adolescent diet in LMICs, future studies should include adolescents who are out of school.

Association between Intake of Energy and Macronutrients and Memory Impairment Severity in US Older Adults, National Health and Nutrition Examination Survey 2011-2014.

Without a cure, dementia affects about 50 million people worldwide. Understanding the effects of dietary habits, a key lifestyle behavior, on memory impairment is critical to inform early behavioral modification to delay further memory loss and progression to dementia. We examined the associations of total energy intake and energy intake from macronutrients with memory impairment among older US adults using data from the nationally representative National Health and Nutrition Examination Survey study 2011-2014. A total of 3623 participants aged ≥60 years were analyzed. Comparing to those with low total energy intake, individuals with high intake were more likely to have severe memory impairment (OR: 1.52, 95% CI: 1.15 to 2.02; ptrend = 0.005). Specifically, higher energy intake from carbohydrate (OR: 1.59, 95% CI: 1.12 to 2.26) and sugar (OR: 1.54, 95% CI: 1.11 to 2.16) were both significantly associated with the presence of memory impairment. Additionally, higher energy intake from fat, carbohydrate and sugar were significantly associated with more server memory impairment (fat: ptrend = 0.04; carbohydrate: ptrend = 0.03; sugar: ptrend = 0.02). High energy intake, either total or from carbohydrates, fat or sugar, is associated with memory impairment severity in the older US population. No such association was found in energy intake from protein.

Prevalence, correlates and misperception of depression symptoms in the United States, NHANES 2015-2018.

PURPOSE: To update the prevalence of depression in the US and identify whether misperception exists in depression assessed by self-report versus validated tools administered by trained professionals. METHODS: We extracted data on sociodemographic characteristics, lifestyle factors, medical conditions, depressive symptoms, and self-reported depressive feeling from National Health and Nutrition Examination Survey (NHANES) study 2015-2018. We calculated the weighted prevalence and 95% CI of depressive symptoms assessed by a validated tool PHQ-9 (score≥10) and self-reported depression respectively. Then, we performed multivariable logistic regressions to identify their sociodemographic and lifestyle correlates. Finally, we calculated the agreement between PHQ-9 assessed depressive symptoms and self-reported depressive feeling to examine possible misperception. RESULTS: The present analysis included a total of 10,257 adults (Weighted N = 215,964,374) aged 20 years and older. Prevalence of depressive symptoms (PHQ-9 score ≥10) were 8.0% from 2015 to 2018 in the US. 19.7% and 11.3% adults reported feeling depressed at least once a month and at least once a week, respectively. Depressive experience was largely misperceived in the US (Kappa agreement = 50.98%, Cohen's Kappa = 0.16, p < 0.001). Particularly, an estimated 1.1 million US adults had depressive symptoms but never felt being depressed. Several consistent demographic and behavioral correlates were identified across the two measures, namely: age, sex, race/ethnicity, poverty and sitting time. CONCLUSIONS: A high prevalence of depression was found, and misperception of depression exists among the US adult population. Our findings highlight an urgent need for health professionals to reduce the burden of depression with considering patients' socioeconomic status and lifestyle factors.

Association of Hot Tea Consumption with Regional Adiposity Measured by Dual-Energy X-Ray Absorptiometry in NHANES 2003-2006.

OBJECTIVE: This study aimed to investigate the potential antiobesity benefits of hot tea consumption at the population level. METHODS: Using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, the association between hot tea consumption and dual-energy x-ray-measured body fat was examined in a large representative sample of US adults (n = 5,681, 51.9% women). RESULTS: Compared with non-tea drinkers, men who consumed 0.25 to 1 cup per day of hot tea had 1.5% (95% CI: 0.4% to 2.6%) and 1.7% (95% CI: 0.4% to 3.0%) less total and trunk body fat, respectively. The associations were stronger among men 45 to 69 years old compared with younger men (20-44 years). For men who consumed 1 or more cups per day of hot tea, lower total (-1.2%, 95% CI: -2.3% to -0.2%) and trunk body fat (-1.3%, 95% CI: -2.6 to -0.1%) was observed among men 45 to 69 years old only. In women, those who drank 1 or more cups per day had 1.5% lower (95% CI: -2.7% to -0.3%) trunk body fat compared with non-tea drinkers. CONCLUSIONS: Consumption of hot tea might be considered as part of a healthy diet in order to support parameters associated with metabolic health and may be particularly important in older male age groups in supporting reduced central adiposity.

Trends and prevalence of nocturia among US adults, 2005-2016.

PURPOSE: Increased nocturia episodes can be a clinical marker of poor health status. The present study aimed to evaluate patterns and temporal trends in nocturia and sociodemographic and lifestyle correlates in the US population. METHODS: Participants, aged 20 years or older, were included in this repeated cross-sectional study. The National Health and Nutrition Examination Survey from 2005 to 2016 was used. Participants were asked "During the past 30 days, how many times per night did you most typically get up to urinate, from the time you went to bed at night until the time you got up in the morning?". Individuals were categorized as either ≥ 1 nocturia episode or ≥ 2 nocturia episodes per night. RESULTS: The estimated prevalence of ≥ 1 nocturia was high among men (20-39 years, 56.8%; 40-59 years, 70.2%; ≥ 60 years, 82.7%) and women (20-39 years, 68.9%; 40-59 years, 74.3%; ≥ 60 years, 84.7%), particularly in Non-Hispanic-blacks. From 2005-2016, the trends in prevalence of ≥ 1 nocturia increased for the age groups 20-39 and 40-59 years among men (p < 0.001 and p = 0.001, respectively) and women 20-39 and 40-59 years (p < 0.001 and p = 0.032, respectively), but a stable trend was observed among men and women who were 60 years and older (p = 0.814, and p = 0.64, respectively). A significant increasing trend of ≥ 2 nocturia episodes was observed among men only aged 40-59 years (p = 0.007). CONCLUSIONS: From 2005 through 2016, the secular trend in the frequency of nocturia increased in both men and women in general, which was significant under the age of 60 years, particularly in Non-Hispanic-blacks.

Carbon nanotube intramolecular p-i-n junction diodes with symmetric and asymmetric contacts.

A p-i-n junction diode based on the selectively doped single-walled carbon nanotube (SWCNT) had been investigated, in which two opposite ends of individual SWCNT channel were doped into the p- and n-type SWCNT respectively while the middle segment of SWCNT was kept as the intrinsic. The symmetric and asymmetric contacts were used to fabricate the p-i-n junction diodes respectively and studied the effect of the contact on the device characteristics. It was shown that a low reverse saturation current of ~20 pA could be achieved by these both diodes. We found that the use of the asymmetric contact can effectively improve the performance of the p-i-n diode, with the rectification ratio enhanced from ~10(2) for the device with the Au/Au symmetric contact to >10(3) for the one with the Pd/Al asymmetric contact. The improvement of the device performance by the asymmetric-contact structure was attributed to the decrease of the effective Schottky-barrier height at the contacts under forward bias, increasing the forward current of the diode. The p-i-n diode with asymmetric contact also had a higher rectification ratio than its counterpart before doping the SWCNT channel, which is because that the p-i-n junction in the device decreased the reverse saturated current.

A p-i-n junction diode based on locally doped carbon nanotube network.

A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~10(4)), large forward current (~12.2 µA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 µm.