Nanosolar has a new CEO, and the name will be familiar to a lot of people in Silicon Valley.

Geoff Tate, the former CEO of Rambus, is the new CEO at Nanosolar, which makes copper indium gallium selenide (CIGS) solar cells. Tate replaces co-founder Martin Roscheisen. The announcement does not mention the sometimes controversial and often outspoken Roscheisen at all. It only quotes Brian Sager, the other co-founder.

Maybe Roscheisen doesn't have a family to spend more time with, so they had to leave that part out. The guy who looks like he's getting his head chopped off in the picture is Martin.

CIGS solar cells hold the promise of being almost as efficient as crystalline silicon solar panels but being less costly to manufacture. Mass-manufacturing CIGS solar cells, however, is extremely difficult. Although investors have invested over $2 billion into CIGS start-ups, most have faced delays and those companies that have shipped modules have largely only shipped limited quantities.

Nanosolar has raised over $500 million from, among others, Mohr Davidow, Larry Page and Sergey Brin. In 2007, the company said it started to ship solar panels to customers. However, the dearth of Nanosolar panels in the wild lead to skepticism and criticism within the industry. Then, in September 2009, Nanosolar said it had begun to mass produce CIGS solar cells and assemble them into modules in the company's module facility in Germany. Nanosolar has signed $4.1 billion worth of contracts to sell panels to, among others, Beck Energy, EDF Energies Nouvelles, AES Solar, Juwi and NextLight Renewable Power. But in solar, a contract is only as good as a company's ability to deliver. If Nanosolar can't fulfill the supply agreements, these companies will go elsewhere.

The company has said its commercial products have an efficiency of around 10 to 12 percent and that it has developed cells in the lab that top 16.4 percent efficiency.

Tate is an interesting choice. Before Rambus, he worked at Advanced Micro Devices. Thus, he brings expertise for managing large mass-manufacturing organizations, something Nanosolar likely needs. Chip execs play a prominent role throughout the solar space. First Solar president Bruce Sohn came from Intel, while New eSolar John Van Scoter came from Texas Instruments. Semi equipment vets Joseph Laia and Chris Gronet head up, respectively, MiaSole and Solyndra, two competing CIGS companies.

But Rambus, where Tate really came to prominence, did not manufacture anything. It invented a new type of memory that it licensed to other semiconductor makers. It was one of the first pure intellectual property companies. Rambus ultimately had to sue a wide variety of companies. The legal controversies made Rambus one of the most feared companies in Silicon Valley. I recall hanging out with Rambus execs at conferences a few years back. It was like eating lunch with Don King.

Is this an indication that Nanosolar may try to license its technology? Who knows. If so, Tate understands royalties and licensing deals better than almost anyone. And what happened to Roscheisen? We will answer these questions when we learn more. In the meantime, here's a video of Sager explaining Nanosolar's high efficiency cells: