Indian-American Silicon Valley venture capitalist Vinod Khosla and his wife Neeru are among the latest billionaires to have pledged half of their vast fortunes to charity either during their lifetime or after death.

56-year-old Khosla is Silicon Valley's most prominent "green" venture capitalist and a dominant personality in the cleantech community. A co-founder of Sun Microsystems, Khosla was a general partner at VC firm Kleiner Perkins Caufield & Byers before striking out on his own with Khosla Ventures in 2004.

As of March, Khosla's net worth was USD 1.4 billion, according to a calculation by Forbes.