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Chang, HJ, Chen CH, Chen* YF, Lin TY, Chen LC, Chen KH, Lan ZH.  2005.  Responseto “Comment on ‘Direct evidence of nanocluster-induced luminescence in InGaNepifilms. Appl. Phys. Lett.. 87:136102-(1-2).
Chang, CK, Hwang JY, Lai WJ, Chen CW, Huang CI, Chen KH, Chen LC.  2010.  Influence of solvent on the dispersion of single-walled carbon nanotubes in polymer matrix and the photovoltaic performance. J. Phys. Chem.. C114:10932-10936.
Chang, CS, Chattopadhyay S, Chen* LC, Chen KH, Chen CW, Chen YF, Collazo R, Sitar Z.  2003.  Band gap dependence of field emission from one dimensional nanostructures grown on n-type and p-type silicon substrates. Phys. Rev.. B68:125322-(1-5).
Chang, YK, Hsieh HH, Pong* WF, Tsai M-H, Chien FZ, Tseng PK, Chen LC, Wang TY, Chen KH, Bhusari DM, Yan JR, Lin ST.  1999.  Quantum confinement effect in diamond nanocrystals studied by X-Ray-absorption spectroscopy. Phys. Rev. Lett.. 82:5377-5380.
Chang, YK, Hsieh HH, Pong WF, Tsai MH, Lee KH, Dann TE, Chien FZ, Tseng PK, Tsang KL, Su WK, Chen LC, Wei SL, Chen KH, Bhusari DM, Chen YF.  1998.  Electronic and Atomic Structures of SiCN Thin Film by X-ray Absorption Spectroscopy and Theoretical Calculations. Phys. Rev.. B58:9018.
Chang, H-C, You H-J, Sankar R, Yang Y-J, Chen L-C, Chen K-H.  2019.  Enhanced thermoelectric performance of BiCuTeO by excess Bi additions, 2019. 45(7, Part A):9254-9259. AbstractWebsite

Thermoelectric (TE) devices used to convert waste heat directly into electricity are highly desirable for alleviating the prevailing energy crisis and global climate-change issues. Among the various TE materials available, metal oxides exhibit high thermal and chemical stabilities in air, and are hence, preferred for use in many TE applications. However, most of them possess TE figures of merit (ZT) that are below the applicable value of 2, in the mid-temperature region (from 250 to 600 °C). In a previous work, the removal of a small amount of Bi from BiCuSeO was found to improve the ZT of BiCuSeO. In this work, we pursue another track and study the TE performance of BiCuTeO after the addition of up to 6% excess Bi. Bi1+xCuTeO (x = 0.00–0.06) samples were prepared by solid-state reactions, followed by hot-pressing to form pellets. By adding a stoichiometric excess of Bi into BiCuTeO, 16% enhancement in power factor was achieved at 450 °C. This enhancement can be attributed to the increase in the Seebeck coefficient because of the appearance of secondary phases. Detailed characterizations and discussions of the effect of the nominal excess Bi in BiCuTeO are presented in this paper. The findings of this study can be applied in the investigation of novel high-performance TE materials.

Chang, YS, Chien CT, Chen* CW, Chu TY, Chiang HH, Ku CH, Wu JJ, Lin CS, Chen LC, Chen KH.  2007.  Structural and optical properties of single crystal Zn1-xMgxO nanorods-experimental and theoretical studies. J. Appl. Phys.. 101:033502.
Chang, HJ, Chen CH, Chen* YF, Lin TY, Chen LC, Chen KH, Lan ZH.  2005.  Direct evidence of nanocluster-induced luminescence in InGaN epifilms. Appl. Phys. Lett.. 86:021911-(1-3).
Chang, CY, Pearton* SJ, Huang PJ, G.C. Chi H, Wang T, Chen JJ, Ren F, Chen KH, Chen LC.  2007.  Control of nucleation site density of GaN nanowires. Appl. Surf. Sci.. 253:3196-3200.
Chang, CY, Chi GC, Wang WM, Chen* LC, Chen KH, Ren F, Pearton SJ.  2006.  Electrical transport properties of single GaN and InN nanowires. J. Electronic Materials. 35:738-743.
Chang, M-C, Ho P-H, Tseng M-F, Lin F-Y, Hou C-H, Lin I-K, Wang H, Huang P-P, Chiang C-H, Yang Y-C, Wang I-T, Du H-Y, Wen C-Y, Shyue J-J, Chen C-W, Chen K-H, Chiu P-W, Chen L-C.  2020.  Fast growth of large-grain and continuous MoS2 films through a self-capping vapor-liquid-solid method, 2020. 11(1):3682. AbstractWebsite

Most chemical vapor deposition methods for transition metal dichalcogenides use an extremely small amount of precursor to render large single-crystal flakes, which usually causes low coverage of the materials on the substrate. In this study, a self-capping vapor-liquid-solid reaction is proposed to fabricate large-grain, continuous MoS2 films. An intermediate liquid phase-Na2Mo2O7 is formed through a eutectic reaction of MoO3 and NaF, followed by being sulfurized into MoS2. The as-formed MoS2 seeds function as a capping layer that reduces the nucleation density and promotes lateral growth. By tuning the driving force of the reaction, large mono/bilayer (1.1 mm/200 μm) flakes or full-coverage films (with a record-high average grain size of 450 μm) can be grown on centimeter-scale substrates. The field-effect transistors fabricated from the full-coverage films show high mobility (33 and 49 cm2 V−1 s−1 for the mono and bilayer regions) and on/off ratio (1 ~ 5 × 108) across a 1.5 cm × 1.5 cm region.

Chang, CC, Lin CF, Chiou JM, Ho TH, Tai Y, Lee JH, Chen YF, Wang JK, Chen LC, Chen* KH.  2010.  Effects of cathode buffer layers on the efficiency of bulk-heterojunction solar cells. Appl. Phys. Lett.. 96:263506.
Chang, H-C, Chen T-H, Sankar R, Yang Y-J, Chen L-C, Chen K-H.  2020.  Highly improved thermoelectric performance of BiCuTeO achieved by decreasing the oxygen content, 2020. 15:100248. AbstractWebsite

BiCuTeO is a promising thermoelectric material owing to its intrinsically low thermal conductivity and high carrier concentration. This study investigated the influence of stoichiometric oxygen deficiencies on the thermoelectric performance of BiCuTeO. Bulk BiCuTeO1−x (0.16 ≥ x) samples were prepared by a conventional solid state reaction and pelleted by hot pressing. Synchrotron X-ray diffraction, electron probe X-ray microanalysis, scanning electron microscopy, and transmission electron microscopy characterized the samples. A maximum value of 1.06 was achieved for the dimensionless figure of merit ZT at 673 K for BiCuTeO0.88, which is approximately 49% better than the current maximal ZT value for BiCuTeO. The power factor was noticeably improved owing to increases in the electrical conductivity and Seebeck coefficient. Moreover, the optimal oxygen deficiency could introduce nanoparticles, resulting in reduced thermal conductivity. The findings will be important for the future development of metal oxide thermoelectric materials for use in practical thermoelectric devices.

Chang, HC, Lin JC, Wu JY, Chen KH.  1995.  Infrared spectroscopy and vibrational relaxation of CHx and CDx stretches on synthetic nanocrystal diamond surfaces. J. Phys. Chem.. 99:11081.
Chang, CY, Lan TW, Chi GC, Chen* LC, Chen KH, Chen JJ, Jang S, Ren F, Pearton SJ.  2006.  Effect of ozone cleaning and annealing on Ti/Al/Pt/Au ohmic contacts on GaN nanowires. Electrochemical and Solid-State Lett.. 9:G155-G157.
Chatterjee, A, Shen CH, Ganguly A, Chen* LC, Hsu CW, Hwang JY, Chen KH.  2004.  Strong room-temperature UV emission of nanocrystalline ZnO films derived from a polymeric solution. Chem. Phys. Lett.. 391:278-282.
Chatterjee, A, Chattopadhyay S, Hsu CW, Shen CH, Chen* LC, Chen CC, Chen KH.  2004.  Growth and characterization of GaN nanowires produced on different sol-gel derived catalyst dispersed in TiO2 and polyvinyl alcohol matrix. J. Mater. Res.. 19:1768-1774.
Chattopadhyay, S, Chen* LC, Wu CT, Chen KH, Wu JS, Chen YF, Lehmann G, Hess P.  2001.  Thermal diffusivity in amorphous silicon carbon nitride thin films by the traveling wave technique. Appl. Phys. Lett.. 79:332-334.
Chattopadhyay, S, Chen* LC, Chien SC, Lin ST, Wu CT, Chen KH.  2002.  Phase and thickness dependence of thermal diffusivity in SiCxNy and BCxNy,. Thin Solid Films. 420:205-211.
Chattopadhyay, S, Shi SC, Wu CT, Chen LC, Chen CH, Chen* KH.  2006.  Self selected apex angle distribution of the nanotips. Appl. Phys. Lett.. 89:143105-(1-3).
Chattopadhyay, S, Chen* LC, Chien SC, Lin ST, Chen KH.  2002.  Bonding characterization, density measurement and thermal diffusivity studies of amorphous silicon carbon nitride and boron carbon nitride thin films. J. Appl. Phys.. 92:5150-5158.
Chattopadhyay, S, Chen LC, Chen KH.  2011.  Energy production and conversion applications ofone-dimensional semiconductor nanostructures. NPG Asia Mater.. 3:74-81.
Chattopadhyay*, S, Shi SC, Lan ZH, Chen CF, Chen KH, Chen LC.  2005.  Molecular sensing with ultrafine silver crystals on hexagonal aluminum nitridenanorodtemplate. J. Am. Chem. Soc.. 127:2820-2821.
Chattopadhyay*, S, Lo HC, Hsu CH, Chen LC, Chen KH.  2005.  Surface enhanced Raman spectroscopy using self assembled silver nanoparticulates on silicon nanotips. Chem. Mater.. 17:553-559.
Chattopadhyay*, S, Chien SC, Chen LC, Chen KH, Lehmann G, Hess P.  2002.  Thermal diffusivity in diamond, SiCxNy and BCxNy. Diamond Relat. Mater. 11:708-713.