CN102780159B - Epitaxial wafer for 980nm F-P cavity strained quantum well laser with narrow line width and preparation method thereof - Google Patents

Abstract

The invention discloses an epitaxial wafer for a 980nm F-P cavity strained quantum well laser with a narrow line width and a preparation method of the epitaxial wafer for the 980nm F-P cavity strained quantum well laser with the narrow line width, and relates to the field of a semiconductor laser. A growth buffer layer, a transition layer, a n-type lower restriction layer, a lower waveguide layer, a lower potential barrier layer, an active layer, an upper potential barrier layer, an upper waveguide layer, a p-type upper restriction layer and an ohmic contact layer are grown on a GaAs substrate layer in sequence so as to be processed into the 980nm F-P cavity strained quantum well laser with the narrow line width. The epitaxial wafer for the 980nm F-P cavity strained quantum well laser with the narrow line width can be applied to the fields, such as optical measurement, solid laser pumping, laser spectroscopy, medical research and the like.

Description

Epitaxial wafer of the 980nm F-P chamber Strained Quantum Well Lasers of low live width and preparation method thereof

Technical field

The present invention relates to field of semiconductor lasers, especially launch the low live width F-P chamber Strained Quantum Well Lasers of 980nm wavelength.

Background technology

980nm semiconductor laser has application very widely in communication and medical field, and it is the window of erbium-doped fiber amplifier pumping source, is also the first-selected wavelength in laser scalpel.Quantum-well laser is a kind of Semiconductor Laser of new development in the last few years.Because its active layer thickness is less than electron mean free path, charge carrier can only be moved at active layer, improve the conversion efficiency of laser.

Live width broadening factor (Linewidth Enhancement Factor, factor) be the key factor that affects semiconductor laser breadth of spectrum line.It not only directly affects the breadth of spectrum line of semiconductor laser, and can be to the mode stable of laser, warbling under current-modulation, and injection locking scope, light amplification coefficient and optical feedback effect etc. all can exert an influence.The quantum-well laser live width broadening factor measured value of bibliographical information is generally 1-3 at present, the impact bringing to dynamic characteristic of laser in order to reduce broadening of spectral lines, realize the output of laser narrow linewidth, need a kind of 980nm F-P chamber Strained Quantum Well Lasers of low live width.

Narrow linewidth semiconductor laser mainly contains distributed feedback laser (DFB), distribution bragg feedback laser (DBR) and grating external-cavity laser at present, these three kinds of lasers have been realized the output of low live width really, are exactly chamber face processing technology complexity [Wang Lili, a Jian Hua, Zhao Tonggang, Xu great Xiong, Rao Lan, Wu Wei, Guo Yongxin 2005 laser technologies 29 4] [the 125th page of Jiang Jianping 2000 semiconductor laser (Beijing: Electronic Industry Press)] but these three kinds of lasers have common difficult point.And for F-P chamber Strained Quantum Well Lasers, its manufacture method is comparatively ripe, but common 980nm F-P chamber Strained Quantum Well Lasers live width is wider, the structure of common 980nm F-P chamber Strained Quantum Well Lasers as shown in Figure 1: 21 is substrate layer, and material is GaAs; 22 is resilient coating, and thickness is 300nm, and material is N-type GaAs; 23 is N-shaped lower limit layer, and thickness is 1400nm, and material is Al _0.5ga _0.5as; 24 is graded bedding, and thickness is 200nm, and material is Al _0.2-0.5ga _0.8-0.5as; 25 for building layer, and thickness is 20nm, and material is GaAs; 26 is active layer, and thickness is 7nm, and material is In _0.2ga _0.8as; 27 for building layer, and thickness is 20nm, and material is GaAs; 28 graded beddings, thickness is 200nm, material is Al _0.5-0.2ga _0.5-0.8as; 29 is limiting layer, and thickness is 1400nm, and material is Al _0.5ga _0.5as; 30 is ohmic contact layer, and thickness is 200nm, and material is GaAs.According to formula for live width, centered by wavelength, for corresponding band width, cfor the light velocity, through calculating the corresponding live width of this laser angular frequency be =2155GHz, live width is wider.

Summary of the invention

In order to solve the problem of existing 980nm F-P chamber Strained Quantum Well Lasers live width existence, the invention provides a kind of epitaxial wafer of 980nm F-P chamber Strained Quantum Well Lasers of low live width.

The present invention includes the GaAs substrate layer, resilient coating, transition zone, N-shaped lower limit layer, lower waveguide layer, lower barrierlayer, active layer, upper barrier layer, upper ducting layer, p-type upper limiting layer and the ohmic contact layer that are linked in sequence.

The present invention is with In _x ga _1-x as material is as the active layer of quantum well structure, using GaAs material as barrier layer, by optimal design active layer 7 thickness and material component, make the live width broadening factor of quantum well band-to-band transition generation and the live width broadening factor of free-carrier Absorption and band-gap narrowing generation drop to minimum.Referring to Fig. 6, live width broadening factor size is about 0, thereby makes live width drop to 2GHz from the 2155GHz of general quantum-well laser.Effectively reduce the spectral width of 980nm F-P chamber quantum-well laser, improved the quality of quantum-well laser light beam.

The material of substrate layer of the present invention is GaAs; The thickness of resilient coating is 100nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3gaAs.The thickness of transition zone is 300nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _x ga _{1- x} as, wherein xbe 0.3～0.7.The thickness of N-shaped lower limit layer is 1500nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as.The thickness of lower waveguide layer is 100nm, and material is Al _0.3ga _0.7as.The thickness of lower barrierlayer is 20nm, and material is GaAs.Active layer, thickness is 8nm, adopts In _x ga _{1- x} as strain gauge material, x=0.196.The thickness of upper barrier layer is 20nm, and material is GaAs.The thickness of upper ducting layer is 100nm, and material is Al _0.3ga _0.7as.The thickness of p-type upper limiting layer is 1500nm, and material is that doping of Zn concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as.The thickness of ohmic contact layer is 300nm, and material is that doping of Zn concentration is 1 × 10 ¹⁹cm ^-3gaAs.

The present invention also provides a kind of preparation method of 980nm F-P chamber Strained Quantum Well Lasers epitaxial wafer of low live width:

Step is as follows:

1) GaAs spending taking (100) deflection <111> direction 15, as substrate, passes into SiH ₄, the thickness of growth GaAs resilient coating reaches 100nm;

2) transition zone of growing on GaAs resilient coating, material is Al _x ga _{1- x} as, wherein, xbe 0.3～0.7, the growth thickness of transition zone is 300nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

3) on transition zone, with Al _0.7ga _0.3as is material, growing n-type lower limit layer, and growth thickness is 1500nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

4) lower waveguide layer that growth thickness is 100nm on N-shaped lower limit layer, material is Al _0.3ga _0.7as, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

5) on lower waveguide layer, the lower barrierlayer taking GaAs Material growth thickness as 20nm;

6), on lower barrierlayer, adopt In _x ga _{1- x} as strain gauge material, wherein x=0.196, setting InGaAs growth temperature is 610 DEG C, and V/III ratio is 100, the active layer that thickness is 8nm;

7) on active layer, the upper barrier layer taking GaAs Material growth thickness as 20nm;

8) on upper barrier layer, the upper ducting layer that growth thickness is 100nm, material is Al _0.3ga _0.7as;

9) on upper ducting layer, with Al _0.7ga _0.3as is material, and the p-type upper limiting layer that growth thickness is 1500nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

10) on p-type upper limiting layer, taking GaAs material, the ohmic contact layer that growth thickness is 300nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁹cm ^-3.

Organometallic thing vapour phase epitaxy (MOCVD) equipment that the present invention can adopt AIXTRON company to produce, completes after above-mentioned processing step, by the SiO of plasma enhanced chemical vapor phase epitaxy technique growth 100nm ₂deielectric-coating, then (width is to form P-type electrode window through ray through conventional photoetching, etching process ), hotter evaporation Au/Zn/Au, form P-type Ohm contact electrode.N surface chemistry is thinned to approximately after thickness, evaporate AuGeNi, form N-type ohmic contact layer.Alloy temperature is , alloying atmosphere is hydrogen.Form the long chip of laser for 1mm in chamber through cleavage, then chip is sintered to heat sink upper, through lead-in wire, complete a kind of 980nm F-P chamber Strained Quantum Well Lasers of low live width.

The present invention can be applicable to the fields such as optical measurement, solid state laser pumping, laser spectroscopy, medical research.

Beneficial effect of the present invention: with In _x ga _1-x as material is as the active layer of quantum well structure, using GaAs material as barrier layer, by optimal design active layer 7 thickness and material component, make the live width broadening factor of quantum well band-to-band transition generation and the live width broadening factor of free-carrier Absorption and band-gap narrowing generation drop to minimum, realize low linewidth factor, and then reduced live width.Effectively reduce the spectral width of quantum-well laser, improved the quality of quantum-well laser light beam.The active layer of the 980nm F-P chamber Strained Quantum Well Lasers of the low live width of the present invention is In _x ga _1-x as material, x=0.196, trap scantling is 8nm, centre wavelength =980nm, =-0.00027, calculate live width 2GHz, the more existing quantum-well laser live width (2155GHz) of live width has reduced by 3 orders of magnitude.The present invention sets about carrying out narrow linewidth design from laser epitaxial structure and material, so, be more than the comparison for F-P cavity semiconductor laser, not with distributed feedback laser (DFB), distribution bragg feedback laser (DBR) and the outside cavity gas laser comparison with optical grating construction.

The principles of science of foundation of the present invention is as follows:

The principal element that affects semiconductor laser live width broadening factor has three aspects, is respectively band-to-band transition, free-carrier Absorption and the impact of band-gap narrowing three on live width broadening factor.Band-to-band transition on live width broadening factor produce impact be on the occasion of, the then generation of both impacts on live width broadening factor is negative value.Concrete computational methods are as follows:

After laser Injection Current, the charge carrier that is injected into active area makes laser generation spontaneous emission, and spontaneous emission can cause that carrier concentration changes, it makes to swash position phase and the discontinuous variation of intensity of penetrating field, and in this process, variation has occurred for refractive index real part and imaginary part. the factor causes that because active area carrier concentration changes laser refractive index real part and imaginary part change generation ^[1,2].

Live width broadening factor can be expressed as:

Wherein Δ n 'for refractive index real part variable quantity, Δ n ' 'for refractive index imaginary part variable quantity, above formula is changed:

Δ nfor the variable quantity of carrier concentration

Have again: Δ n ' '=Δ gc/(2 ω) (3)

Wherein Δ gfor change in gain amount, ωfor angular frequency, cfor the light velocity in vacuum;

Have according to document [3]: Δ n '/ Δ i= (n/ λ)Δ λ/ Δ i, nfor refractive index, for the variable quantity of wavelength, for the variable quantity of electric current.For convenience of calculating, desirable following approximate:

Δ n’= n Δ ω/ω (4)

Δ ωfor angular frequency variable quantity, bring (3) and (4) formula into (2) formula, arrangement obtains the approximate formula of the factor:

dg/dNthe slope that is gain peak variation matched curve under each carrier concentration, the differential gain directly reflects the speed that band edge carrier concentration increases, not only with semiconductor laser factor-related, also relevant with a lot of other important performances. d ω/dNfor the slope of the corresponding photon energy variation of gain peak under each carrier concentration matched curve.So, obtain after material gain and the variation of corresponding photon energy with carrier concentration, by (5) formula, we just can be right the factor is calculated.The peak value that we select gain curve under each carrier concentration in computational process with and corresponding photon energy calculate.

The variation of refractive index imaginary part causes jointly by band-to-band transition, free carrier effect and band-gap narrowing, and the variable quantity that then both cause is very little ^[2]so, in the time that calculating three factor refractive index imaginary parts affect, the impact of approximate use band-to-band transition on imaginary part, that is:

Order , ;

Δ n ₁' (Δ n ₁' '), Δ n ₂' (Δ n ₂' '), Δ n ₃' (Δ n ₃' ') represent successively the variation of real (void) portion of refractive index that band-to-band transition, band-gap narrowing and free carrier effect cause, represent that successively they are right the impact of the factor.

Band-gap transition pair effects of Factors

When obtaining the differential gain dg/dNand d ω/dNafter, can calculate band-to-band transition pair the impact of the factor:

Band-gap narrowing pair effects of Factors

The increase of carrier concentration can cause that band gap diminishes, and this is many bulk effects.Band-gap narrowing amount Δ e _g=-1.6 × 10 ^-8( n+ p) ^1/3(eV) ^[2], according to formula (5), intrinsic material n=P, have:

Free carrier effect pair effects of Factors

The contribution of free carrier plasma effect refractive index real part is ^[2]:

Change according to formula (3):

Differential is carried out to carrier concentration respectively in formula (10) and (11), has

For convenience of calculation, we measure approximation to photon energy: ω ≈ E _qso, can obtain free carrier effect pair by formula (2), (10) and (11) the contribution of the factor is:

According to computational methods recited above, first we calculated the gain curve of quantum well.

The gain formula of considering relaxation effect in current-carrying subband is ^[4,5]:

Wherein = h/ 2 πreduced Planck constant, qfor electron charge, m ₀for electron rest mass, ε ₀for permittivity of vacuum, ρ _r = m _r/ π L _w ² for reduced state density, l _wfor quantum well trap wide, oscillator effective mass m _r= m _x* m _c/ ( m _x+ m _c), m _xfor the heavy hole corresponding with transition or light hole effective mass. Τfor the relaxation time is got 0.1ps, e _qfor the band gap of quantum well structure.We adopt comparatively common a kind of band gap calculation form to calculate e _g: e _g=1.424-1.5817 x+ 0.5137 x ²(eV) ^[6].Spin coupling split separation reference literature [5], its fitting formula should be Δ=0.34-0.11 x+ 0.15 x ²(eV), e _lfor the self-energy of continuous distribution oscillator, f _c, f _vbe respectively conduction band and valence-band level by the probability of electrons occupy,

, be the difference at the bottom of conduction band quasi-Fermi level and conduction band.

, be the difference of top of valence band and valence band quasi-Fermi level.

| m _t | ²for moment of momentum array element.

Other parameters all adopt interpolation method to carry out matching.

In order to simplify calculating, we only calculate conduction band the first subband that material is had to major effect e _c1with heavy hole the first subband e _hh1the gain that transition produces ^[6,7].

InGaAs/GaAs quantum well can be with simplified structure as shown in Figure 3 ^[6,8].Δ e _c, Δ e _vbe respectively conduction band band rank, valence band heavy hole band rank, Δ is compared on band rank e _c: Δ e _v=3:2 ^[9].

There is the son in depth stop potential well can be with and can obtain from following formula ^[2,10]

m _bfor the effective mass of conduction band (or valence band) potential barrier, m _wfor the effective mass of conduction band (or valence band) trap material, Δ efor band rank.

980nm laser In component and the wide relation of trap

The relation of the wide and In component of 980nm InGaAs quantum-well laser trap as shown in Figure 4.We utilize said method to calculate respectively each group of data pair the impact of the factor, as shown in Fig. 5-7.Along with the increase of In component, what trap was wide reduces, the factor is constantly increased by negative value, and wide at trap is 8nm, and In component is 0.196 o'clock, the factor reaches absolute value minimum.Therefore, it is 8nm that the present invention uses trap wide, and In component is that 0.196 pair of laser designs.

The calculating of live width

nfor carrier concentration, sfor photon concentration, σ is Spontaneous Emission Factor, and Δ τ is carrier lifetime.

Brief description of the drawings

Fig. 1 is common 980nm F-P chamber Strained Quantum Well Lasers structural representation.

Fig. 2 is the 980nm F-P chamber Strained Quantum Well Lasers structural representation of low live width of the present invention.

Fig. 3 is InGaAs/GaAs quantum well band structure schematic diagram.

Fig. 4 is the graph of a relation of the wide and In component of 980nm quantum-well laser trap.

Fig. 5 is αthe factor is with the wide changing trend diagram of 980nm quantum-well laser trap.

Fig. 6 is αthe factor is with 980nm quantum-well laser In change of component tendency chart.

Fig. 7 is αthe factor is with the wide and In component three dimensional change tendency chart with 980nm quantum-well laser trap.

Embodiment

One, prepare epitaxial wafer:

Organometallic thing vapour phase epitaxy (MOCVD) equipment that the present invention adopts AIXTRON company to produce, procedure of processing is as follows:

1) GaAs spending taking (100) deflection <111> direction 15, as substrate, passes into SiH ₄, the thickness of growth GaAs resilient coating reaches 100nm;

2) transition zone of growing on GaAs resilient coating, material is Al _x ga _{1- x} as, wherein, xbe 0.3～0.7, the growth thickness of transition zone is 300nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

3) on transition zone, with Al _0.7ga _0.3as is material, growing n-type lower limit layer, and growth thickness is 1500nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

4) lower waveguide layer that growth thickness is 100nm on N-shaped lower limit layer, material is Al _0.3ga _0.7as, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

5) on lower waveguide layer, the lower barrierlayer taking GaAs Material growth thickness as 20nm;

6), on lower barrierlayer, adopt In _x ga _{1- x} as strain gauge material, wherein x=0.196, setting InGaAs growth temperature is 610 DEG C, and V/III ratio is 100, the active layer that thickness is 8nm;

7) on active layer, the upper barrier layer taking GaAs Material growth thickness as 20nm;

8) on upper barrier layer, the upper ducting layer that growth thickness is 100nm, material is Al _0.3ga _0.7as;

9) on upper ducting layer, with Al _0.7ga _0.3as is material, and the p-type upper limiting layer that growth thickness is 1500nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

10) on p-type upper limiting layer, taking GaAs material, the ohmic contact layer that growth thickness is 300nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁹cm ^-3.

Two, prepare the 980nm F-P chamber Strained Quantum Well Lasers of low live width:

By the SiO of plasma enhanced chemical vapor phase epitaxy technique growth 100nm ₂deielectric-coating, then (width is to form P-type electrode window through ray through conventional photoetching, etching process ), hotter evaporation Au/Zn/Au, form P-type Ohm contact electrode.N surface chemistry is thinned to approximately after thickness, evaporate AuGeNi, form N-type ohmic contact layer.Alloy temperature is , alloying atmosphere is hydrogen.Form the long chip of laser for 1mm in chamber through cleavage, then chip is sintered to heat sink upper, through lead-in wire, complete the 980nm F-P chamber Strained Quantum Well Lasers of low live width.

Three, epitaxial slice structure feature:

The GaAs substrate layer 1, resilient coating 2, transition zone 3, N-shaped lower limit layer 4, lower waveguide layer 5, lower barrierlayer 6, active layer 7, upper barrier layer 8, upper ducting layer 9, p-type upper limiting layer 10 and the ohmic contact layer 11 that are linked in sequence as shown in Figure 2.

The material of substrate layer 1 is GaAs; The thickness of resilient coating 2 is 100nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3gaAs.The thickness of transition zone 3 is 300nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _x ga _{1- x} as, wherein xbe 0.3～0.7.The thickness of N-shaped lower limit layer 4 is 1500nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as.The thickness of lower waveguide layer 5 is 100nm, and material is Al _0.3ga _0.7as.The thickness of lower barrierlayer 6 is 20nm, and material is GaAs.The thickness of active layer 7 is 8nm, is In _x ga _{1- x} as strain gauge material, x=0.196.The thickness of upper barrier layer 8 is 20nm, and material is GaAs.The thickness of upper ducting layer 9 is 100nm, and material is Al _0.3ga _0.7as.The thickness of p-type upper limiting layer 10 is 1500nm, and material is that doping of Zn concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as.The thickness of ohmic contact layer 11 is 300nm, and material is that doping of Zn concentration is 1 × 10 ¹⁹cm ^-3gaAs.

Substrate 1 adopts N-shaped GaAs material, for carrying out the epitaxial growth of each layer of laser thereon.

Resilient coating 2 adopts N-shaped GaAs material, is produced on substrate layer 1.This layer of effect is to grow the epitaxial loayer that defect is few, reduces the stress between substrate and other layers, to grow high-quality epi-layer surface, wherein mixed Si impurity, and doping content is 1 × 10 ¹⁸cm ^-3.(" doping content is 1 × 10 herein ¹⁸cm ^-3" refer to: in the mixture of Si and the formation of GaAs material, Si is as impurity, and the content of Si accounts for 1 × 10 of mixture total amount ¹⁸cm ^-3.All descriptions for doping content all therewith roughly the same below.）

The material that transition zone 3 adopts is Al _x ga _{1- x} as, Al component xchange to 0.7 from 0.3, be produced on resilient coating 2, its objective is the stress reducing between resilient coating 2 and N-shaped lower limit layer 4, reduce the defect of growth material, wherein doping content is 1 × 10 ¹⁸cm ^-3, mix Si impurity.

N-type lower limit layer 4 adopts Al _0.7ga _0.3as material, is produced on transition zone 3, its objective is and suppresses the propagation of laser transverse mode to substrate layer 1 and resilient coating 2, reduces luminous energy loss, has also played the effect of limiting carrier diffusion simultaneously, has reduced threshold current.Wherein doping content is 1 × 10 ¹⁸cm ^-3, mix Si impurity.

Lower waveguide layer 5 adopts Al _0.3ga _0.7as material, is produced on lower limit layer 4, and its effect is the propagation of restriction light, improves the beam quality of laser.

Lower barrierlayer 6 adopts GaAs material, is produced on lower waveguide layer 5, and its effect is for active layer provides potential barrier, makes carrier confinement among active layer, realizes quantization effect.

What active layer 7 used is InGaAs material, is produced on lower barrierlayer 6, and its effect is for quantum-well laser provides source region, produces photon, realizes the gain of light.Described active layer adopts In _x ga _1-x as strain gauge material, x=0.196.

Upper barrier layer 8 adopts GaAs material, is produced on lower active layer 7, and its effect is for active layer provides potential barrier, makes carrier confinement among active layer, realizes quantization effect.

Upper ducting layer 9 adopts Al _0.3ga _0.7as material, is produced on barrier layer 8, and its effect is the propagation of restriction light, improves the beam quality of laser.

P type upper limiting layer 10 adopts Al _0.7ga _0.3as material, is produced on ducting layer 9, its objective is and suppresses the propagation of laser transverse mode to ohmic contact layer, reduces luminous energy loss, has also played the effect of limiting carrier diffusion simultaneously, has reduced threshold current.Wherein doping content is 1 × 10 ¹⁸cm ^-3, mix Zn impurity.

Ohmic contact layer 11 adopts p-type GaAs material, is produced on p-type upper limiting layer 10, its objective is and realizes ohmic contact, improves conversion efficiency and power output.Wherein doping content is 1 × 10 ¹⁹cm ^-3, mix Zn impurity.

The present invention is with In _x ga _1-x as material is as the active layer of quantum well structure, using GaAs material as barrier layer, by optimal design active layer 7 thickness and material component, make the live width broadening factor of quantum well band-to-band transition generation and the live width broadening factor of free-carrier Absorption and band-gap narrowing generation drop to minimum.Referring to Fig. 6, live width broadening factor size is about 0, thereby makes live width drop to 2GHz from the 2155GHz of general quantum-well laser.Effectively reduce the spectral width of 980nm F-P chamber quantum-well laser, improved the quality of quantum-well laser light beam.

As seen from Figure 3:

In the optimizing process of online wide broadening factor, can be by design In _x ga _1-x wide and the In component of the trap of As/GaAs quantum well, regulates conduction band the first subband in band structure e _c1with heavy hole the first subband e _hh1, obtain the structure of live width broadening factor minimum.

As seen from Figure 4:

At design 980nm In _x ga _1-x when As/GaAs semiconductor laser, along with the wide increase of quantum well trap, In component xconstantly reduce.

As seen from Figure 5:

Along with the wide increase of trap, 980nm In _x ga _1-x the live width broadening factor size of As/GaAs semiconductor laser is totally increase trend, approaches 0 most for 8nm place live width broadening factor trap is wide.

As seen from Figure 6:

With the wide corresponding In component of 980nm semiconductor laser trap xconstantly increase, live width broadening factor size is and reduces trend, x=0.2 left and right approaches 0 most.

Be Fig. 5 and Fig. 6 stereo display after comprehensive by Fig. 7, can find out clearly wide at trap is 8nm, corresponding In component x=the live width broadening factor at 0.196 place approaches 0 most, and this laser will have better line width characteristic.

Claims (2)

1. an epitaxial wafer for the 980nm F-P chamber Strained Quantum Well Lasers of low live width, comprises the GaAs substrate layer, resilient coating, transition zone, N-shaped lower limit layer, lower waveguide layer, lower barrierlayer, active layer, upper barrier layer, upper ducting layer, p-type upper limiting layer and the ohmic contact layer that are linked in sequence; The thickness of described resilient coating is 100nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3gaAs; The thickness of described transition zone is 300nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _x ga _{1- x} as; The thickness of described N-shaped lower limit layer is 1500nm, and material is that doping Si concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as; The thickness of described lower waveguide layer is 100nm, and material is Al _0.3ga _0.7as; The thickness of described lower barrierlayer is 20nm, and material is GaAs; The thickness of described upper barrier layer is 20nm, and material is GaAs; The thickness of described upper ducting layer is 100nm, and material is Al _0.3ga _0.7as; The thickness of described p-type upper limiting layer is 1500nm; The thickness of described ohmic contact layer is 300nm;

It is characterized in that: in described transition zone, doping Si concentration is 1 × 10 ¹⁸cm ^-3al _x ga _{1- x} in As xbe 0.3～0.7; The thickness of described active layer is 8nm, adopts In _x ga _{1- x} as strain gauge material, x=0.196; The material of described p-type upper limiting layer is that doping of Zn concentration is 1 × 10 ¹⁸cm ^-3al _0.7ga _0.3as; The material of described ohmic contact layer is that doping of Zn concentration is 1 × 10 ¹⁹cm ^-3gaAs.

2. the preparation method of the epitaxial wafer of the 980nm F-P chamber Strained Quantum Well Lasers of low live width as claimed in claim 1, is characterized in that comprising the following steps:

1) GaAs spending taking (100) deflection <111> direction 15, as substrate, passes into SiH ₄, the thickness of growth GaAs resilient coating reaches 100nm;

2) transition zone of growing on GaAs resilient coating, material is Al _x ga _{1- x} as, wherein, xbe 0.3～0.7, the growth thickness of transition zone is 300nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

3) on transition zone, with Al _0.7ga _0.3as is material, growing n-type lower limit layer, and growth thickness is 1500nm, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

4) lower waveguide layer that growth thickness is 100nm on N-shaped lower limit layer, material is Al _0.3ga _0.7as, passes into SiH when growth ₄, the Si doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

5) on lower waveguide layer, the lower barrierlayer taking GaAs Material growth thickness as 20nm;

6), on lower barrierlayer, adopt In _x ga _{1- x} as strain gauge material, wherein x=0.196, setting InGaAs growth temperature is 610 DEG C, and V/III ratio is 100, the active layer that thickness is 8nm;

7) on active layer, the upper barrier layer taking GaAs Material growth thickness as 20nm;

8) on upper barrier layer, the upper ducting layer that growth thickness is 100nm, material is Al _0.3ga _0.7as;

9) on upper ducting layer, with Al _0.7ga _0.3as is material, and the p-type upper limiting layer that growth thickness is 1500nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁸cm ^-3;

10) on p-type upper limiting layer, taking GaAs material, the ohmic contact layer that growth thickness is 300nm, passes into DEZn when growth, and the Zn doping content of this epitaxial loayer is 1 × 10 ¹⁹cm ^-3.