BOSTON – October 29, 2008 – Srinivas Sridhar, Ph.D., dis­tin­guished pro­fessor and chair of Physics at North­eastern Uni­ver­sity, Evin Gul­tepe and their team of researchers from the university’s Elec­tronic Mate­rials Research Insti­tute have demon­strated a tech­nique to assemble single-​​walled carbon nan­otubes (SWNT) into three-​​dimensional struc­tures. This tech­nique will be useful for the large scale, accel­er­ated assembly of SWNTs at room tem­per­a­ture, which is more suit­able for nanoscale elec­tronic appli­ca­tions, such as flat panel dis­plays and elec­tronic memory devices.

(Image: A cross-​​sectional view of SEM micro­graphs of assem­bled SWNTs in anodic alu­mina array fab­ri­cated on Silican)

This research was pub­lished in an October 2008 issue of the journal Nan­otech­nology.

The elec­tronic prop­er­ties of SWNTs, such as large cur­rent capac­i­ties and quick mobility, makes them one of the most highly researched struc­tures for the devel­op­ment of nanoscale elec­tronics. They are able to con­duct energy more quickly and effi­ciently than cur­rent struc­tures and pro­vide a plat­form from which to build smaller-​​scale prod­ucts. Widely used mate­rials, such as copper, do not meet the require­ments as effec­tive elec­trical inter­con­nects on a smaller scale.

The chal­lenge of uti­lizing carbon nan­otubes (CNT) in the nanoscale is to assemble them into three-​​dimensional struc­tures for large scale appli­ca­tions. Cur­rently, man­u­fac­turing CNTs requires growing or assem­bling them into a device, which requires very hot tem­per­a­tures and com­plex post-​​assembly pro­ce­dures. In con­trast, a post-​​synthesis assembly method allows for the arrange­ment of CNTs in ambient tem­per­a­tures, which gives more flex­i­bility in the man­u­fac­turing process.

In this newly dis­cov­ered process, Gul­tepe, Sridhar and their col­leagues man­u­fac­tured nan­otem­plates, with bil­lions of nano-​​sized holes in which to house the SWNTs. Uti­lizing elec­trical fields, they were able assemble the SWNTs ver­ti­cally into the alu­mina nan­otem­plate, with a sil­ican sub­strate bottom layer and a metal top layer. The vertically-​​assembled three-​​dimensional SWNTs pro­vide the elec­trical inter­con­nec­tion between the nan­otem­plates and the sil­icon substrates.

The greatest sig­nif­i­cance of this process is the poten­tial to man­u­fac­ture three-​​dimensional SWNTs elec­trical inter­con­nects at a high-​​rate and on a larger scale,” said Sridhar, who is also the Director of the Elec­tronic Mate­rials Research Insti­tute at North­eastern. “Scaling down the nom­inal fea­ture size means greater per­for­mance and decreased costs.”

In addi­tion to Sridhar, the team of researches involved with this project includes Ahmed Bus­naina, Ph.D., Director of Northeastern’s Center for High-​​rate Nanoman­u­fac­turing, Dat­tatri Nagesha, Ph.D., Bernard Did­dier Fred­eric Casse, Ph.D., and Sel­vapraba Sel­varasah. This research was sup­ported by the IGERT Nanomed­i­cine Sci­ence and Tech­nology and the NSF Nanoscale Sci­ence and Engi­neering Cen­ters Program.

For more infor­ma­tion about Pro­fessor Sridhar’s research, please con­tact Jenny Eriksen at (617) 373‑2802 or via email at j.​eriksen@​neu.​edu.

About North­eastern University

Founded in 1898, North­eastern Uni­ver­sity is a pri­vate research uni­ver­sity located in the heart of Boston. North­eastern is a leader in inter­dis­ci­pli­nary research, urban engage­ment, and the inte­gra­tion of class­room learning with real-​​world expe­ri­ence. The university’s dis­tinc­tive coop­er­a­tive edu­ca­tion pro­gram, where stu­dents alter­nate semes­ters of full-​​time study with semes­ters of paid work in fields rel­e­vant to their pro­fes­sional inter­ests and major, is one of the largest and most inno­v­a­tive in the world. The Uni­ver­sity offers a com­pre­hen­sive range of under­grad­uate and grad­uate pro­grams leading to degrees through the doc­torate in six under­grad­uate col­leges, eight grad­uate schools, and two part-​​time divi­sions. For more infor­ma­tion, please visit www​.north​eastern​.edu.