The Unexpected Tech

Alta Devices: Finding a Solar Solution

(Flexible power: Alta’s solar cells can be made into bendable sheets. In this sample, a series of solar cells are encapsulated in a roofing material. Credit: Gabriela Hasbun)

Alta Devices is a small but well-funded startup located in the same nondescript Silicon Valley office building that once served as the headquarters for Solyndra, the infamous solar company that went bankrupt last year after burning through hundreds of millions of dollars in public and venture investments. Whether the location has bad karma is still not clear, jokes Alta’s CEO, Christopher Norris. But Norris, a former semiconductor-industry executive and venture capitalist, does know that the fate of his company will hinge on its ability to navigate the risky and expensive process of scaling up its novel technology, which he believes could produce power at a price competitive with fossil-fuel plants and far more cheaply than today’s solar modules.

On a table in Alta’s conference room, Norris lays out samples of the company’s solar cells, flexible black patches encapsulated in clear plastic. They look unremarkable, but that’s because the key ingredient is all but invisible: microscopically thin sheets of gallium arsenide. The semiconductor is so good at absorbing sunlight and turning it into electricity that one of Alta’s devices, containing an active layer of gallium arsenide only a couple of micrometers thick, recently set a record for photovoltaic efficiency. But gallium arsenide is also extremely expensive to use in solar cells, and thin films of it tend to be fragile and difficult to fabricate. In fact, Alta’s innovations lie not in choosing the material—the semiconductor has been used in solar cells on satellites and spacecraft for decades—but in figuring out how to turn it into solar modules cheap enough to be practical for most applications.