Summary of the invention
The technical problem to be solved in the present invention provides a kind of ZnO/ZnMgO multi-quantum trap ultraviolet laser diode and preparation method thereof.
ZnO/ZnMgO multi-quantum trap ultraviolet laser diode of the present invention, substrate are the n type GaN that is grown on the sapphire; Have successively by ZnO and Mg from bottom to top at substrate
1-xZn
xThe ZnO/Zn that the O alternating deposit forms
1-xMg
xO multiple quantum well active layer, p type NiO thin layer and first electrode; Also have second electrode and ZnO/Zn
1-xMg
xThe O multiple quantum well active layer is deposited on the n type GaN rete side by side, wherein ZnO/Zn
1-xMg
x0.1≤x of O multiple quantum well active layer≤0.3.
Described ZnO/Zn
1-xMg
xThe O multiple quantum well active layer is by the ZnO film in 3~10 cycles and Zn
1-xMg
xThe structure that the O film alternately forms.
Described first electrode is Au, Pt, Pt/Ni or Au/Ni.
Described second electrode is In, Al, Ga or Ag.
The invention also discloses the preparation method of above-mentioned ZnO/ZnMgO multi-quantum trap ultraviolet laser diode, concrete steps are as follows: adopting the n type GaN that is grown on the sapphire is substrate, at first clean substrate, on n type GaN substrate, replace sputter ZnO film and Zn by rf magnetron sputtering technology then with semiconductor technology
1-xMg
xThe O film forms ZnO/Zn
1-xMg
xThe O multiple quantum well active layer; At ZnO/Zn
1-xMg
xReactive sputtering p type NiO thin layer on the O multiple quantum well active layer; Plate first electrode by rf magnetron sputtering technology on p type NiO surface at last, plate second electrode at n type GaN edge.
By rf magnetron sputtering prepared ZnO/Zn
1-xMg
xIn the process of O multiple quantum well active layer, the target of preparation ZnO film is the ZnO ceramic target, preparation Zn
1-xMg
xThe target of O film is Mg and ZnO hybrid target, and background air pressure is not more than 10 during sputter
-3Pa, underlayer temperature is 200~400 ℃, air pressure is 0.5~5Pa, relative partial pressure of oxygen O during deposition
2/ (O
2+ Ar) be 15~40%, sputtering power 60~150W, every layer of sputtering time be 1~3 minute.
Preparation Zn
1-xMg
xThe target of O film is selected the mixed target of Mg metallic target and ZnO ceramic target for use, and wherein the area ratio of Mg metallic target and ZnO ceramic target is 1: 0.5~1.5.
At ZnO/Zn
1-xMg
xIn the process of reactive sputtering p type NiO thin layer, adopt the Ni metallic target on the O multiple quantum well active layer, relatively partial pressure of oxygen O
2/ (O
2+ Ar) be 50~70%, the cavity background air pressure before the sputter is not more than 10
-3Pa, underlayer temperature are that 150~400 ℃, sputtering pressure are that 0.5~5Pa, sputtering power 80~200W, sputtering time are 20~60 minutes.
Beneficial effect of the present invention is:
1. use ZnO/Zn
1-xMg
xThe O Multiple Quantum Well has improved the recombination probability of charge carrier in the ZnO trap greatly, has made full use of the advantage of ZnO semi-conducting material broad stopband and big exciton binding energy, has improved luminous efficiency.By rational designs and material preparation process optimization, realized ultraviolet freely swash penetrate luminous;
2. adopt the n type GaN that is grown on the Sapphire Substrate as substrate, as ZnO/Zn
1-xMg
xThe electron injecting layer of O multiple quantum well active layer, this substrate and ZnO/Zn simultaneously
1-xMg
xThe O Multiple Quantum Well has realized good lattice match, has improved ZnO/Zn
1-xMg
xThe crystal mass of O Multiple Quantum Well has reduced non-radiative compoundly, has improved electricity greatly and has caused ultra-violet light-emitting intensity.
3. adopt p type NiO as hole injection layer, the relative ZnO of energy gap is bigger under its room temperature, has given full play to the super injection advantage of heterojunction; Simultaneously, there is Ni in the NiO film
2+The room, make film at room temperature present natural hole conduction, thereby avoided the influence of excessive doping crystal mass.
4. the present invention adopts rf magnetron sputtering systems produce multiple quantum well active layer, greatly reduces cost, helps realizing industrialization production.
Embodiment
With reference to Fig. 1, ZnO/ZnMgO multi-quantum trap ultraviolet laser diode of the present invention, substrate is for being grown in the n type GaN (2) on the sapphire (1); Have successively by ZnO and Mg from bottom to top at substrate
1-xZn
xThe ZnO/Zn that the O alternating deposit forms
1-xMg
xO multiple quantum well active layer (3), p type NiO thin layer (4) and first electrode (5) also have second electrode (6) and ZnO/Zn
1-xMg
xO multiple quantum well active layer (3) is deposited on n type GaN (2) rete side by side, wherein ZnO/Zn
1-xMg
x0.1<x≤0.3 of O multiple quantum well active layer (3).
Embodiment 1:
1. substrate cleans: adopting the n type GaN that is grown on the sapphire is substrate, is cut into 15mm * 15mm size, adopts acetone, alcohol, deionized water to distinguish ultrasonic cleaning 3 minutes, dries up with nitrogen gun at last.
2.ZnO/Zn
1-xMg
xThe growth of O multiple quantum well active layer: the substrate after the surface clean is put into the growth room of rf magnetron sputtering system, and the growth room is evacuated to background air pressure 5 * 10
-4Pa, heated substrate to temperature is 250 ℃.Select the target of ZnO ceramic target as deposition ZnO potential well layer for use, the mixed target of selecting Mg metallic target and ZnO ceramic target for use is as deposition Zn
1-xMg
xThe target of O barrier layer, wherein the area ratio of Mg metallic target and ZnO ceramic target is 2: 3, the Zn of this condition preparation
1-xMg
xX=0.1 in the O layer.Before plated film, pre-sputter 10min is to remove the impurity of target material surface.Use the method for rf magnetron sputtering on n type GaN, alternately to deposit ZnO film layer and Zn then
0.9Mg
0.1The O thin layer, the ZnO/Zn in 10 cycles of formation
0.9Mg
0.1The O mqw active layer.250 ℃ of deposition substrate temperature; Air pressure 0.5Pa during deposition; Relative partial pressure of oxygen O
2/ (O
2+ Ar) be 40%, power 60W; Sputtering time 1min/ layer.
3.p the preparation of type NiO: the method for using reactive sputtering is at ZnO/Zn
0.9Mg
0.1Deposition NiO film on the O mqw active layer.Before plated film, pre-sputter 5min is to remove the impurity of target material surface.Target is selected highly purified metal Ni target, background air pressure 5 * 10 for use
-4Pa, deposition substrate temperature: 150 ℃; Deposition pressure: 0.5Pa, partial pressure of oxygen O relatively
2/ (O
2+ Ar) be 50%; Power: 120W, sputtering time: 30min.
4. the preparation of electrode: adopt the method for rf magnetron sputtering to prepare the Au electrode down as first electrode 100 ℃ of NiO film surfaces, sedimentation time is 15s.The n type GaN of substrate surface goes up plating In as second electrode.
The electroluminescent spectrum figure that records the ZnO/ZnMgO multi-quantum trap ultraviolet laser diode that present embodiment 1 makes under the room temperature as shown in Figure 2.
Embodiment 2:
1. substrate cleans: adopting the n type GaN that is grown on the sapphire is substrate, is cut into 15mm * 15mm size, adopts acetone, alcohol, deionized water to distinguish ultrasonic cleaning 3 minutes, dries up with nitrogen gun at last.
2.ZnO/Zn
1-xMg
xThe growth of O multiple quantum well active layer: the substrate after the surface clean is put into the growth room of rf magnetron sputtering system, and the growth room is evacuated to background air pressure 1 * 10
-3Pa, heated substrate to temperature is 200 ℃.Select the target of ZnO ceramic target as deposition ZnO potential well layer for use, the mixed target of selecting Mg metallic target and ZnO ceramic target for use is as deposition Zn
1-xMg
xThe target of O barrier layer, wherein the area ratio of Mg metallic target and ZnO ceramic target is 1: 1, the Zn of this condition preparation
1-xMg
xX=0.18 in the O layer.Before plated film, pre-sputter 10min is to remove the impurity of target material surface.Use the method for rf magnetron sputtering on n type GaN, alternately to deposit ZnO film layer and Zn then
0.82Mg
0.18The O thin layer, the ZnO/Zn in 3 cycles of formation
0.82Mg
0.18The O mqw active layer.200 ℃ of deposition substrate temperature; Air pressure 5.0Pa during deposition; Relative partial pressure of oxygen O
2/ (O
2+ Ar) be 20%, power 150W; Sputtering time 3.0min/ layer.
3.p the preparation of type NiO: the method for using reactive sputtering is at ZnO/Zn
0.82Mg
0.18Deposition NiO film on the O mqw active layer.Before plated film, pre-sputter 5min is to remove the impurity of target material surface.Target is selected highly purified metal Ni target, background air pressure 5 * 10 for use
-4Pa, deposition substrate temperature: 400 ℃; Deposition pressure: 5.0Pa, partial pressure of oxygen O relatively
2/ (O
2+ Ar) be 70%; Power: 200W, sputtering time: 60min.
4. the preparation of electrode: adopt the method for rf magnetron sputtering to prepare the Pt electrode down as first electrode 100 ℃ of NiO film surfaces, sedimentation time is 15s.The n type GaN of substrate surface goes up plating Ag as second electrode.The electroluminescent spectrum figure that records the ZnO/ZnMgO multi-quantum trap ultraviolet laser diode that present embodiment 2 makes under the room temperature as shown in Figure 3.
Embodiment 3:
1. substrate cleans: adopting the n type GaN that is grown on the sapphire is substrate, is cut into 15mm * 15mm size, adopts acetone, alcohol, deionized water ultrasonic cleaning 3min respectively, dries up with nitrogen gun at last.
2.ZnO/Zn
1-xMg
xThe growth of O multiple quantum well active layer: the substrate after the surface clean is put into the growth room of rf magnetron sputtering system, and the growth room is evacuated to background air pressure 1 * 10
-3Pa, heated substrate to temperature is 300 ℃.Select the target of ZnO ceramic target as deposition ZnO potential well layer for use, the mixed target of selecting Mg metallic target and ZnO ceramic target for use is as deposition Zn
1-xMg
xThe target of O barrier layer, wherein the area ratio of Mg metallic target and ZnO ceramic target is 1: 1, the Zn of this condition preparation
1-xMg
xX=0.18 in the O layer.Before plated film, pre-sputter 10min is to remove the impurity of target material surface.Use the method for rf magnetron sputtering on n type GaN, alternately to deposit ZnO film layer and Zn then
0.82Mg
0.18The O thin layer, the ZnO/Zn in 5 cycles of formation
0.82Mg
0.18The O mqw active layer.300 ℃ of deposition substrate temperature; Air pressure 1.0Pa during deposition; Relative partial pressure of oxygen O
2/ (O
2+ Ar) be 15%, power 100W; Sputtering time 1.5min/ layer.
3.p the preparation of type NiO: the method for using reactive sputtering is at ZnO/Zn
0.82Mg
0.18Deposition NiO film on the O mqw active layer.Before plated film, pre-sputter 5min is to remove the impurity of target material surface.Target is selected highly purified metal Ni target, background air pressure 5 * 10 for use
-4Pa, deposition substrate temperature: 300 ℃; Deposition pressure: 2.0Pa, partial pressure of oxygen O relatively
2/ (O
2+ Ar) be 50%; Power: 80W, sputtering time: 30min.
4. the preparation of electrode: adopt the method for rf magnetron sputtering to prepare the Au/Ni electrode down as first electrode 100 ℃ of NiO film surfaces, sedimentation time is 20s.The n type GaN of substrate surface goes up plating Al as second electrode.
The electroluminescent spectrum figure that records the ZnO/ZnMgO multi-quantum trap ultraviolet laser diode that present embodiment 3 makes under the room temperature as shown in Figure 4.
Embodiment 4:
1. substrate cleans: adopting the n type GaN that is grown on the sapphire is substrate, is cut into 15mm * 15mm size, adopts acetone, alcohol, deionized water ultrasonic cleaning 3min respectively, dries up with nitrogen gun at last.
2.ZnO/Zn
1-xMg
xThe growth of O multiple quantum well active layer: the substrate after the surface clean is put into the growth room of rf magnetron sputtering system, and the growth room is evacuated to air pressure 1 * 10
-3Pa, heated substrate to temperature is 400 ℃.Select the target of ZnO ceramic target as deposition ZnO potential well layer for use, the mixed target of selecting Mg metallic target and ZnO ceramic target for use is as deposition Zn
1-xMg
xThe target of O barrier layer, wherein the area ratio of Mg metallic target and ZnO ceramic target is 2: 1, the Zn of this condition preparation
1-xMg
xX=0.3 in the O layer.Before plated film, pre-sputter 10min is to remove the impurity of target material surface.Use the method for rf magnetron sputtering on n type GaN, alternately to deposit ZnO film layer and Zn then
0.7Mg
0.3The O thin layer, the ZnO/Zn in 8 cycles of formation
0.7Mg
0.3The O mqw active layer.400 ℃ of deposition substrate temperature; Air pressure 0.8Pa during deposition; Relative partial pressure of oxygen O
2/ (O
2+ Ar) be 15%, power 120W; Sputtering time 1.5min/ layer.
3.p the preparation of type NiO: the method for using reactive sputtering is at ZnO/Zn
0.7Mg
0.3Deposition NiO film on the O mqw active layer.Before plated film, pre-sputter 5min is to remove the impurity of target material surface.Target is selected highly purified metal Ni target, base vacuum 1 * 10 for use
-3Pa, deposition substrate temperature: 300 ℃; Deposition pressure: 1.5Pa, partial pressure of oxygen O relatively
2/ (O
2+ Ar) be 50%; Power: 120W, sputtering time: 20min.
4. the preparation of electrode: adopt the method for rf magnetron sputtering to prepare the Pt/Ni electrode down as first electrode 100 ℃ of NiO film surfaces, sedimentation time is 15s.The n type GaN of substrate surface goes up plating Ga as second electrode.
The electroluminescent spectrum figure that records the ZnO/ZnMgO multi-quantum trap ultraviolet laser diode that present embodiment 4 makes under the room temperature as shown in Figure 5.
From embodiments of the invention as can be seen, the ZnO/ZnMgO multi-quantum trap ultraviolet laser diode of preparation has rectification characteristic and luminescent properties preferably, the ultraviolet that this ultraviolet laser diode sends wavelength 373 (± 3) nm freely swashs penetrates laser, single swash penetrate optical linewidth less than 0.5nm, threshold current density 4.7A/cm
2