CN101698932A

CN101698932A - Method for preparing P type cobalt-doped zinc oxide film

Info

Publication number: CN101698932A
Application number: CN200910236797A
Authority: CN
Inventors: 王丽; 苏雪琼; 陈江博; 万晓婧
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2009-10-30
Filing date: 2009-10-30
Publication date: 2010-04-28
Anticipated expiration: 2029-10-30
Also published as: CN101698932B

Abstract

The invention relates to a method for preparing a P type cobalt-doped zinc oxide film. By taking ZnO and Co2O3 as raw materials, the invention obtains a Zn0.9Co0.1O ceramic target material through grinding, mixing, sintering, grinding, pressing and sintering; then, a Pulse Laser Deposition (PLD) method is adopted to prepare the P type cobalt-doped zinc oxide film by the Zn0.9Co0.1O ceramic target material. The invention has simple and easy operation and high repetition rate, and the prepared diluted magnetism semiconductor film has good crystallization quality and smooth surface; and above all, an n type eigen ZnO is successfully transformed into a P type doped ZnO group diluted magnetism semiconductor material; and a favorable precondition is created for the application of preparing a ZnO group homogeneous P-N junction with a diluted magnetism property in the next step.

Description

A kind of method for preparing P type cobalt-doped zinc oxide film

Technical field

The present invention relates to a kind of method of the P of preparation type cobalt-doped zinc oxide film.

Background technology

Utilize the charge property and the spin character of electronics can make semiconducter device that is used for information processing and the magneticsubstance that is used for information storage respectively.And to make the device that has information processing and information storage function simultaneously, then the most important condition is the semiconductor material that obtains to have room-temperature ferromagnetic.The zno-based dilute magnetic semiconductor is one of research focus of room-temperature ferromagnetic semiconductor material, and intrinsic ZnO presents the n type more, and carrier concentration is up to 10 ¹⁹Cm ^-3, mix but can't carry out effective P type, therefore can not realize the basic p-n junction in semi-conductor and the photoelectric device.Preparing a kind of is the P type, and the semiconductor material that possesses the room temperature ferromagnetic characteristic again is a problem anxious to be solved.

People such as K.Sato utilize the electronic structure that has calculated the adulterated ZnO of magnetic transition metal based on the Korringa-Kohn-Rostoker (KKR) of local density approximation, calculation result shows: for the ZnO:TM material (TM is a transition metal) of intrinsic, V, Cr, Fe, Co, the adulterated ZnO of Ni is stable at ferrimagnetic state; The adulterated ZnO of p type (hole conduction) is stable at ferrimagnetic state; The adulterated ZnO of n type (electronic conduction) is stable in antiferromagnetic state; Under the adulterated situation of n type, (Zn, Mn) the O system does not change (K.Sato from antiferromagnetic state to ferrimagnetic state, H.Katayama-yoshida.Material Design forTransparent Ferromagnets with Zno-Based Magnetic Semiconduetors.J.APPI.Phys, 2000,39:L555-558).T.Dietl and H.Ohno have predicted the p type GaN and the ZnO (T.Dietl of manganese ion doping theoretically in 2000, H.Ohno, F.Matsukura, J.Cibert, D.Ferrand.Zener Model Description ofFerromagnetism in Zinc-Blende Magnetic Semiconductors[J] .Science, 2000,287 (11): 1019-1022.).But above research only limits to Theoretical Calculation, does not have actual experiment support.

The Ueda reported first of Japan Osaka university the PLD legal system to be equipped with Co ZnO thin film doped, and the doping of finding to have only Co presents room-temperature ferromagnetic (K.Ueda less than 10% ZnO:Co, H.Tabata, T.Kawai.Magnetic and electric properties of transition-metal-dopedZnO films.Appl.Phys.Lett., 2001,79 (7): 988-990) people such as .Prellier utilizes the metallic target deposit film of Zn and Co in oxygen atmosphere, discover the raising of adopting two target alternating deposit films to help uniformity of film, and find when the volume of Co is 5%, the Curie temperature of film is near room temperature (W.Prellier, A.Fouchet, B.Mercey, et al.Laserablation ofCo:ZnO films deposited from Zn and Co metal targets on (0001) Al2O3substrates.Appl.Phys.Lett., 2003,82 (20): 3490-3492).Human PLD methods such as Rode prepare Zn on sapphire _1-xCo _xThe O film is by measuring Zn _0.75Co _0.25The M-T curve of the null field cooling ZFC/ field cooling FC of O film, having got rid of the Co cluster is the possibility in ferromegnetism source, and think that the ferromegnetism of film is from film intrinsic (Zn, Co) O phase (RODE K, ANANE A, MATTANAR.et al.Magnetic semiconductors based on cobalt substituted ZnO[J] .J Appl Phys, 2003,93:7676-7678.).Do not mention all in above-mentioned several the researchs that the gained film presents the P-type semiconductor characteristic.

Summary of the invention

The method that the purpose of this invention is to provide a kind of P of preparation type cobalt-doped zinc oxide film.

Purpose of the present invention is achieved through the following technical solutions: adopt the solid reaction sintering process to prepare Zn earlier _0.9Co _0.1The O ceramic target, adopt again pulsed laser deposition (concrete steps are as follows for Pulse Laser deposition, PLD) preparation P type cobalt-doped zinc oxide film:

1) preparation Zn _0.9Co _0.1The O ceramic target:

With the ZnO of purity 〉=99.99% and the Co of purity 〉=99.99% ₂O ₃Be after mixing at 0.9: 0.05 and grinding 2～10 hours, in 850～1200 ℃ of insulations 6～12 hours, to be cooled to room temperature in molar ratio, regrinding was pressed into the solid target after 2～10 hours, and the solid target in 850～1200 ℃ of insulations 6～12 hours, is obtained Zn _0.9Co _0.1The O ceramic target;

2) preparation P type cobalt-doped zinc oxide film:

With the Zn for preparing in the step 1) _0.9Co _0.1The O pottery is a target, is substrate with sapphire, single crystalline Si or silica glass, adopts the pulsed deposition legal system to be equipped with P type cobalt-doped zinc oxide film, and vacuum chamber is evacuated to 2.5 * 10 ^-4～2.5 * 10 ^-5Behind the Pa, obstructed any atmosphere, regulate laser power to 200～600mw, target and substrate vertically are placed on the plumage brightness sputter direction, regulate target-substrate distance to 4-5cm, while rotary target material and substrate, and adjust spot size and the position makes the complete covering substrate of plumage brightness front end according to plumage brightness size, with guarantee the film surface that plated even, substrate is heated to 700～800 ℃, open baffle plate, deposit 20～60 minutes.

The beneficial effect that the present invention has:

The present invention adopts pulsed laser deposition with the Co ion ZnO that evenly mixes, and under the prerequisite of not disruptive oxidation zinc structure, allows the position of Co ionic replacement Zn.Not only prepare good, the ganoid diluted semi-conductor thin-film of crystalline quality, also successfully make n type intrinsic ZnO change the P-type semiconductor material into simultaneously, the good premise condition has been created in the application that has the zno-based homogeneous P-N junction of rare magnetic properties for next step preparation.

Description of drawings

The x-ray photoelectron of Zn element can spectrogram (XPS) in the P type cobalt-doped zinc oxide film of Fig. 1, embodiment 1 preparation.Zn element chemistry valence state has kept Zn as can be seen ²⁺, the Co element doping does not influence the structure of ZnO.

The x-ray photoelectron of Co element can spectrogram (XPS) in the P type cobalt-doped zinc oxide film of Fig. 2, embodiment 1 preparation.Co element chemistry valence state has kept Co as can be seen ²⁺, and peak position is higher, illustrates that the doping content of Co is higher.

The magnetic hysteresis loop that the P type cobalt-doped zinc oxide film of Fig. 3, embodiment 1 preparation records with the alternating gradient magnetometer in room temperature, specimen is 3 * 3 millimeters scope zones, P type film has kept the above ferromegnetism of room temperature preferably as can be seen, and Curie temperature is about room temperature.

The surface topography map that the P type cobalt-doped zinc oxide film of Fig. 4, embodiment 1 preparation records with atomic force microscope (AFM).Be film 5 * 5 micrometer range surfaces shown in the figure, the climax height has only 47.5nm, and surfaceness has only 2.61nm, illustrates that the surface is very smooth.

The invention will be further described below in conjunction with the drawings and specific embodiments.

Embodiment

Embodiment 1

1) preparation Zn _0.9Co _0.1The O ceramic target:

With 14.2621g purity is that 99.99% ZnO and 1.5297g purity are 99.99% Co ₂O ₃(mol ratio is 0.9: 0.05) put into the agate beveller and ground after 3 hours, place the corundum sintering container in 5 hours, to be warming up to 1200 ℃ and be incubated 6 hours, be cooled to room temperature, in the agate beveller, grind after 4 hours once more, press target drone (12MPa suppressed 3 minutes down) to be pressed into the circular target of solid that diameter is 30mm through hydraulic pressure, the circular target of solid is put into tube furnace in 1200 ℃ of insulations 11 hours, obtain purity and be 99.99% Zn _0.9Co _0.1The O ceramic target;

2) preparation P type cobalt-doped zinc oxide film:

With the Zn for preparing in the step 1) _0.9Co _0.1The O pottery is a target, with Al ₂O ₃Monocrystalline is a substrate, adopts the pulsed deposition legal system to be equipped with P type cobalt-doped zinc oxide film, and vacuum chamber is evacuated to 2.5 * 10 ^-4Pa, obstructed any atmosphere, adopt and transfer Q Nd:YAG pulsed laser, optical maser wavelength 355nm, repetition rate 10Hz, pulsewidth 10ns, by plasma plume brightness size and shape, regulate lens, target position, target-substrate distance to 5cm, laser power is to 400mw, and then the adjustment light path, facula position and spot size, make the complete covering substrate of plumage plasma brightness front end, the closure molecule pump, vacustat is to 0.78Pa by the time, substrate is heated to 800 ℃, and allow laser to target surface bombardment 3 minutes, and open baffle plate, deposit 20 minutes.

Embodiment 2

1) with the step 1) among the embodiment 1;

2) except that vacuum chamber is evacuated to 1.1 * 10 ^-4Pa and substrate is heated to 700 ℃, other are operated all with the step 2 among the embodiment 1).

Embodiment	Thickness (cm)	Resistivity (ohm-cm)	Mobility (cm^2/V.S)	Carrier concentration (1/cm^3)	Hall coefficient (cm^3/C)	Conduction type
Embodiment	Thickness (cm)	Resistivity (ohm-cm)	Mobility (cm^2/V.S)	Carrier concentration (1/cm^3)	Hall coefficient (cm^3/C)	Conduction type	??1	??5.10E-06	??7.53E-03	??5.66E-01	??1.47E+21	??4.26E-03	The P type
??2	??8.70E-06	??9.55E-02	??2.86E-01	??2.29E+20	??2.73E-03	The P type	??1	??5.10E-06	??7.53E-03	??5.66E-01	??1.47E+21	??4.26E-03	The P type

The Zn of table 1 embodiment 1-2 preparation _0.9Co _0.1The Hall effect detected result of O film.

Claims

1. a method for preparing P type cobalt-doped zinc oxide film is characterized in that, may further comprise the steps:

1) preparation Zn _0.9Co _0.1The O ceramic target:

2) preparation P type cobalt-doped zinc oxide film:

With the Zn for preparing in the step 1) _0.9Co _0.1The O pottery is a target, is substrate with sapphire, single crystalline Si or silica glass, adopts the pulsed deposition legal system to be equipped with P type cobalt-doped zinc oxide film, and vacuum chamber is evacuated to 2.5 * 10 ^-4～2.5 * 10 ^-5Pa, obstructed any atmosphere is regulated laser power to 200～600mw, regulates target-substrate distance to 4-5cm, adjusts spot size and position, and rotary target material and substrate are heated to 700～800 ℃ with substrate simultaneously, open baffle plate, deposit 20～60 minutes.