A photovoltaic device is provided. It comprises at least two electrical contacts, p type dopants and n type dopants. It also comprises a bulk region and nanowires in an aligned array which contact the bulk region. All nanowires in the array have one predominant type of dopant, n or p, and at least a portion of the bulk region also comprises that predominant type of dopant. The portion of the bulk region comprising the predominant type of dopant typically contacts the nanowire array. The photovoltaic devices' p-n junction would then be found in the bulk region. The photovoltaic devices would commonly comprise silicon.