Patent Number: 
Section: claims

1. An electrical generator system including:a radionuclide material;metal electrodes; andelectrical contacts connected to said metal electrodes, said electrical contacts being adapted to facilitate flow of electrical energy when connected to a load,wherein the system further includes a thin layer of zinc oxide having a thickness between 150-1500 nanometers (nm), said thin layer of zinc oxide being in direct contact with at least one of the metal electrodes and forming a metal-semiconductor junction therebetween, andwherein radioactive emissions received from said radionuclide material are converted into electrical energy at said metal-semiconductor junction. 2. The electrical generator system of claim 1, wherein said zinc oxide layer is formed on a substrate material. 3. The electrical generator system of claim 2, wherein said substrate material is selected from glass, sapphire or quartz. 4. The electrical generator system according to claim 2, wherein a layer of a doped metal oxide material is disposed between the zinc oxide layer and the substrate. 5. The electrical generator system according to claim 4, wherein one of said metal electrodes is disposed in direct contact with said doped metal oxide material. 6. The electrical generator system according to claim 1, wherein said thin layer of zinc oxide is formed by an RF magnetron sputter process. 7. The electrical generator system according to claim 1, wherein said metal electrodes are formed of gold, silver or aluminium. 8. The electrical generator system according to claim 1, wherein said metal electrodes are deposited on said zinc oxide by a sputtering process or electrochemical vapour deposition. 9. The electrical generator system according to claim 1, wherein said radionuclide material is encased in a seal material. 10. The electrical generator system according to claim 9, wherein said seal material is selected from aluminium, a metal alloy, plastic or Mylar. 11. The electrical generator system according to claim 1, wherein said radionuclide material is selected from Sr-90, Pm-147, Ni-63 or H-3. 12. An electrical power supply device including a housing enclosing an electrical generator system according to claim 1. 13. The device of claim 12, wherein there are multiple layers of zinc oxide, each layer having corresponding metal electrodes and electrical contacts, wherein adjacent layers are separated by an insulating substrate material.