CN101252255A

CN101252255A - Semiconductor silicium THz laser source device

Info

Publication number: CN101252255A
Application number: CNA2008100340775A
Authority: CN
Inventors: 陆卫; 余晨辉; 张波; 李天信; 陈平平; 李宁; 李志锋; 陈效双
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2008-02-29
Filing date: 2008-02-29
Publication date: 2008-08-27

Abstract

The invention discloses a semiconductor silicon Terahertz laser source part, comprising a pumping source, a silicon THz laser chip and a refrigerating system providing refrigeration for the silicon THz laser chip. The semiconductor silicon Terahertz laser source part is characterized in that the silicon THz laser chip has hydrogen-like shallow donor impurity NSD with ionization power of 40.09meV and a longer 2p0 level Lifetime to substitute an impurity P in the silicon THz laser chip so as to realize laser output at the wave band of 5.40THz. The semiconductor silicon Terahertz laser source part has the advantage that population inversion is realized easily between 2p0 energy level and lower S state, the quality factor of the THz laser source part is improved around 3 times compared with the laser source part of V-like shallow donor impurity in silicon, greatly improving the efficiency and performance of THz laser source part. The preparation method of the silicon material adopted on the part is pulling method which is mature in technology and sound in evenness.

Description

Semiconductor silicium THz laser source device

Technical field

The present invention relates to semiconductor silicon Terahertz (THz) lasing light emitter device, specifically be meant a kind of semiconductor silicon lasing light emitter device of 5.40THz wave band.

Background technology

(electromagnetic radiation in 300GHz～10THz) is interval promptly is so-called Terahertz (THz) radiation at 1mm～30 μ m between wavelength between millimeter wave and the infrared light.Interaction between THz radiation and various multi-form material has caused this wave band region memory in application prospects, as chemical detection, astronomical science, gas sensing and medical imaging etc.Many characteristic peaks of the vibrational spectrum of the phonon frequency of condensed state matter, big molecule (comprising biomolecule such as protein) are all in the THz wave band.Charge carrier in condensed state matter and the liquid also has high-sensitive response to the THz radiation.Abundant physics or chemical information all contain among the THz of material spectrum.Novel THz laser coherence light source, with the peculiar property of its radiation will various ultrafast process detections in the condensed state system, field such as broadband communications, high speed photoelectronic device, material sign, unmarked biochip, medical diagnosis is widely used.

But, because all there is not effective terahertz emission source generating method all the time, lack the light solid-state THz light source of low-power consumption, cause people very limited to the understanding of the character of THz wave band electromagnetic radiation.With respect to wave bands such as other infrared, microwaves of being studied extensively and profoundly, the THz wave band is called as human to the blank area in the electromagnetic spectrum understanding.The application of this wave band is limited by the shortage of efficient light sources, stagnates for a long time, hesitates to move forward.

Present stage comparative maturity the THz light source in the middle of, mostly volume is bigger, the corollary system complexity has brought difficulty for the miniaturization of equipment.The THz radiation source that has only the based semiconductor material is a Solid State Source, and its advantage is that volume is little, and application adaptability is strong, is subjected to generally showing great attention to.In THz radiation source based on semi-conducting material, based on the THz radiation source of silicon materials are one of ideal radiation sources of expecting most of people, mainly be because this type of radiation source can be with existing than ripe integrated high silicon process technology compatibility, be easy to realize low-costly and in high volume development and production, can promote the THz broad application fast.At present, accomplished based on the THz laser of hydrogen-like shallow donor impurity phosphorus (P) in the silicon, key is to exist among the impurity P 2p longer than the ground state life-span ₀Energy level.If longer 2p arranged with a kind of ₀The hydrogen-like shallow donor impurity substitutional impurity P of the life time of the level is used to produce THz laser, and this laser will have higher quality factor, have clear superiority.

Summary of the invention

Based on above-mentioned existing situation, purpose of the present invention will provide a kind of the utilization to have longer 2p in the silicon exactly ₀The hydrogen-like shallow donor impurity of the life time of the level excite the output that is implemented in high-quality-factor THz laser in the silicon.

Semiconductor silicium THz laser source device of the present invention comprises: pumping source, silicon THz chip of laser provide the refrigerating system of refrigeration for silicon THz chip of laser.

The pump light that pumping source 1 produces, reflect the silicon THz chip of laser 4 that enters on the cold platform that is placed on refrigerating system 5 through forming pumping laser, this pumping laser of satisfying the requirement of silicon THz chip of laser behind the laser emission attenuator 2 through speculum 3, it is characterized in that: the 2p that enters the hydrogen-like shallow donor impurity NSD of pumping laser in silicon of silicon THz chip of laser 4 ₀Energy level is set up population inversion, and then produces the laser of 5.40THz wave band.

Said refrigerating system 5 is the liquid helium refrigerating system, and system temperature is adjustable between 4.2K～20K.

Said pumping source 1 is CO ₂Mid-infrared laser, wavelength is between 9.2-10.7 μ m.

Said THz chip of laser is one to have hydrogen-like shallow donor impurity NSD, and impurity concentration is 10 ¹⁴～10 ¹⁶Cm ^-3Silicon chip.

The course of work of lasing light emitter device of the present invention is as follows substantially:

Start pump laser, send infrared high intensity laser beam.The energy of pumping laser only need get final product greater than hydrogenic impurity ionization energy in theory.Consider the influence of pumping, preferably be chosen in the pumping laser in the mid infrared region the population inversion efficient of generation THz laser.

The THz chip of laser is the silicon materials chip that comprises a hydrogen-like shallow donor impurity NSD, and the ionization energy of this impurity NSD is 40.09meV.After this chip was subjected to mid-infrared laser and excites, electronics was excited to conduction band on the hydrogen-like shallow donor impurity NSD ground state, forms non-equilibrium free charge charge carrier.By energy level and the spontaneous transition of NSD impurity bound level at the bottom of conduction band after releasing energy with acoustics or optical phonon interaction, the relaxation process that these electronics enter behind the shallow donor impurity NSD constraint center at last is a quick cascade process.In this chip NSD impurity, because 2p ₀The adjacent low-yield s attitude energy level of energy gap is far away, and electronics by being suppressed with the interactional relaxation process of acoustical phonon, causes 2p on this energy level ₀Energy level has longer life with respect to low-lying level s attitude etc., is excited to behind the conduction band transition again and gets back to 2p ₀The electron accumulation of energy level has been to a certain degree just having surpassed the electron number that is on the low-lying level s attitude, thereby realized population inversion.As the shallow donor impurity in the silicon materials, NSD is the same with P, As, Sb etc., its 2p ₀The wave band of electron radiation is just just at the THz wave band between energy level and the low-lying level s attitude.But this shallow donor impurity NSD 2p ₀Approximately be 3 times of impurity P corresponding life time of the level the life time of the level, shows as NSD impurity 2p on the spectrum ₀The halfwidth of energy level (FWHM) is about the 2p of impurity P ₀1/3 of energy level FWHM.The former is 2p ₀Energy level FWHM is about 44 μ eV, latter 2p ₀Energy level FWHM is about 140 μ eV.Accordingly, be about 651 based on the quality factor q that comprises NSD impurity silicon materials THz laser, be about 243 based on the quality factor q that comprises impurity P silicon materials THz laser, the former is 3 times of the latter approximately.

Major advantage of the present invention is as follows:

In based on silicon in the THz lasing light emitter device of shallow donor impurity transition between the energy levels mechanism, with the more long-life 2p newfound, that material itself has ₀The shallow donor impurity NSD of energy level substitutes known V such as P, As, Sb family impurity.In the silicon materials, shallow donor impurity NSD 2p ₀Be about 2p such as P, As, Sb the life time of the level ₀More than three times of the life time of the level, corresponding quality factor based on the silica-based THz lasing light emitter device that comprises this NSD shallow donor impurity also obtains about three times raising.

Description of drawings

Fig. 1 is a semiconductor silicon THz lasing light emitter device architecture simplified schematic diagram of the present invention.

Fig. 2 is the physical principle figure that THz chip of laser of the present invention produces the THz radiation.

Fig. 3 is the comparison diagram of NSD shallow donor impurity spectral line live width and the corresponding spectral line live width of P shallow donor impurity in the THz chip of laser of the present invention.

Embodiment

Below in conjunction with drawings and Examples the specific embodiment of the present invention is described in further detail:

In the present invention, with CO ₂Mid-infrared laser is as pump excitation source 1, and wavelength is between 9.2-10.7 μ m.Pump spectrum light is through attenuator 2 and speculum 3 guiding back incidents and begin to excite THz chip of laser 4.

THz chip of laser used in the present invention is that one to have the hybrid class be shallow donor impurity NSD, and ionization energy is 40.09meV, and the impurity optium concentration is 10 ¹⁴～10 ¹⁶Cm ^-3Between.This silicon adopts the czochralski method preparation, is of a size of 10 * 10 * 7mm ³

Refrigerating system 5 used in the present invention adopts liquid helium as cold-producing medium, auxiliary alternating temperature temperature-controlling system, and system temperature is adjustable between 4.2K～20K.Consider factors such as signal to noise ratio and power, it is more suitable that temperature is controlled at below the 17K.

Comprise the radiation of other wave band in the radiation that the back is sent because the THz chip of laser is stimulated, therefore need adopt filter 6 to carry out filtering, export through

speculum

7,8 through filter 6 filtered light beams at its output.

Match whole Optical Maser System according to structure chart shown in Figure 1, adopt the specifications parameter that example described in detail, the quality factor of these Laser Devices is based on have an appointment 3 times the improve of the quality factor of the Laser Devices of V family impurity in the silicon.This laser produces the THz laser that obtains, and wave band is near 5.40THz.

Claims

1. semiconductor silicium THz laser source device comprises: pumping source (1), silicon THz chip of laser (4) provide the refrigerating system (5) of refrigeration for silicon THz chip of laser;

The pump light that pumping source (1) produces, behind laser emission attenuator (2), form and satisfy the pumping laser that silicon THz chip of laser (4) requires, pumping laser reflects the silicon THz chip of laser (4) that enters on the cold platform that is placed on refrigerating system through speculum (3), it is characterized in that:

Enter the 2p of the hydrogen-like shallow donor impurity NSD of pumping laser in silicon of silicon THz chip of laser (4) ₀Energy level is set up population inversion, and then produces the laser of 5.40THz wave band.

2. according to a kind of semiconductor silicium THz laser source device of claim 1, it is characterized in that: said refrigerating system (5) is the liquid helium refrigerating system, and system temperature is adjustable between 4.2K～20K.

3. according to a kind of semiconductor silicium THz laser source device of claim 1, it is characterized in that: said pumping source (1) is CO ₂Mid-infrared laser, wavelength is between 9.2-10.7 μ m.

4. according to a kind of semiconductor silicium THz laser source device of claim 1, it is characterized in that: said THz chip of laser is one to have impurity concentration 10 ¹⁴～10 ¹⁶Cm ^-3The silicon chip of hydrogen-like shallow donor impurity NSD.