Method of producing a partly or completely semi-insulating or p-type doped ZnO substrate, substrates obtained, and electronic, electro-optic or optoelectronic devices comprising them
Method of producing a partly or completely semi-insulating or p-type doped ZnO substrate from an n-type doped ZnO substrate, in which the n-type doped ZnO substrate is brought into contact with an anhydrous molten salt chosen from anhydrous molten sodium nitrate, lithium nitrate, potassium nitrate and rubidium nitrate. Partly or completely semi-insulating or p-type doped ZnO substrate, said substrate being in particular in the form of a thin layer, film or in the form of nanowires; and said substrate being doped at the same time by an element chosen from Na, Li, K and Rb; by N; and by O; it being furthermore possible for ZnO or GaN to be epitaxially grown on this substrate. Electronic, optoelectronic or electro-optic device such as a light-emitting diode (LED) comprising this substrate.
1. A method comprising:
producing a partly or completely semi-insulating or p-type doped ZnO substrate from an n-type doped ZnO substrate;
wherein said producing comprises bringing the n-type doped ZnO substrate into contact with an anhydrous molten salt chosen from the group consisting of anhydrous molten sodium nitrate, lithium nitrate, potassium nitrate and rubidium nitrate.
2. The method according to claim 1 , in which the contacting is carried out at a molten salt temperature of 264° C. to 600° C., and the salt is anhydrous lithium nitrate.
3. The method according to claim 2 , in which the contacting is carried out at a molten salt temperature of 350 to 500° C.
4. The method according to claim 1 , in which the contacting is carried out for a time of 5 minutes to 24 hours.
5. The method according to claim 4 , in which the contacting is carried out for a time of 5 hours.
6. The method according to claim 1 , in which the molten salt is subjected to a dehydration heat treatment before the contacting.
7. The method according to claim 6 , in which the dehydration heat treatment is carried out prior to the contacting by bringing the molten salt up to a sufficient temperature and by keeping this sufficient temperature constant for a time sufficient for the salt to be made anhydrous.
8. The method according to claim 7 , in which the sufficient temperature is 450 to 500° C., and the sufficient time is 24 to 48 hours.
9. The method according to claim 1 , in which the contacting is carried out by immersing the n-type doped ZnO substrate in the molten salt.
10. The method according to claim 1 , in which a surface film layer of the n-type doped ZnO substrate is converted into p-type doped ZnO.
11. The method according to claim 10 , in which the surface film layer is a thin layer film with a thickness of 500 nm to 1 micron.
12. The method according to claim 1 , in which the entire n-type doped ZnO substrate is converted into p-type doped ZnO.