GaAs의 결정성장 및 물성연구

정양준 木浦大學校基礎科學硏究所 1986 基礎科學硏究誌 Vol.4 No.-

A horizontal Bridgman furnace was used for the investigation of relationships between the GaAs growth parameter and the growth characteristics. As source temperature, thermal gradient in the growth region, growth speed, and the temperature for synthesis are the main growth parameters here and the apparatus was designed to control independently the parameters. Unintentially doped GaAs grown near the As source temperature of 617℃ showed the lowest etch pits density. The characteristic terraced etch pits density on Ga face was observed to decrease remarkably when the crystals were doped with In or Ga₂O₂and the doped GaAs crystals showed very high resistivity.

GaAs 단결정 성장 (I)

정양준 木浦大學校基礎科學硏究所 1985 基礎科學硏究誌 Vol.3 No.-

A horizontal Bridgman-type apparatus is described which was designed and constructed for the investigation of relationships between the properties of GaAs crystals and crystal growth parameter. This apparatus use a set of parallel resistance system for pertinent thermal profile and seeding with out the presence of viewing window. Growth parameter, such as thermal gradient in the growth region, arsenic source temperature, and the pulling speed can be independently controlled. During operation, thermal stability better then±0.15℃ is realized ; thermal gradients was 10-12℃/cm in the crystal growth region and can be varied ; the pulling speed was 6mm/hr and can be varied from 2mm/hr 12mm/hr. Surface morphology of GaAs in HNO₃-2H₂O etching system has been studied by scanning electron microscopy. On the (111)Ga plane, terraced pits were formed. However, on the (III)As plane triangular pits were formed. It was found that the melt temperature must be maintained as close as possible to the melting and the crystal grown in short time.

열벽 적층 성장법에 의한 자성 반도체 Zn_1-xMnxTe 에피층의 성장과 특성

정양준,최용대 목포대학교 기초과학연구소 2000 基礎科學硏究誌 Vol.18 No.-

In this study, semimagnetic Zn1-χMnχTe epilayers were epitaxially grown by hot wall epitaxy, and their characterization were systematically examined. The maximum Mn composition χ of the Zn1-χMnχTe epilayers was χ=0.97. The crystallographic orientation and the structure of the Zn1-χMnχTe epilayers were the (100) orientation and the zincblende structure, respectively, identical to those of the GaAs substrate. Mn composition χ increased with increasing the substrate temperature, and the epilayers of the good quality were grown when the substrate temperature was 350∼370℃. Both the lattice constants and the bandgap energy linearly increased with increasing Mn composition χ.

광전소자를 위한 고품질 ZnTe 단결정 박막의 성장과 특성

정양준,김대중,유영문,최용대 한국결정성장학회 2003 韓國結晶成長學會誌 Vol.13 No.3

Zincblende 구조를 갖는 양질의 ZnTe(100) 박막을 $CaAs(100\pm2^{\circ})$ 기판에 HWE법으로 성장하였다 기판온도에 따른 표면상태와 성장률 그리고 결정성의 변화를 관측하였고, 기판온도가 $470^{\circ}C$일 때 결정성이 가장 우수하였다. 10K 광발광 측정으로부터 열적 인장스트레인에 의하여 분리된 가벼운 양공과 무거운 양공을 관측하였고 이들의 일차 들뜬상태를 관측하였다 무거운 양공의 자유 엑시톤의 이중구조는 엑시톤-폴라리톤 결합에 의한 세로방향 엑시톤과 가로방향 엑시톤 사이의 에너지 차이 때문이다. High quality zincblende ZnTe(100) epilayers have been grown on semi-insulating $CaAs(100\pm2^{\circ})$substrate by hot-wall epitaxy. To grow high quality ZnTe epilayers, the growth temperature dependence of the surface topography, the growth rate, and the crystalline properties were investigated. From the photoluminescence measured at 10 K, the light hole and heavy hole free exciton emissions splitted by thermal tensile strain were observed and their first excited state emissions were also measured. The low temperature doublet of the heavy hole free exciton is because of the energy separation between longitudinal exciton and transverse exciton due to exciton-polariton coupling.

HOT WALL EPITAXY방법에 의한 ZnTe/GaAs(100) 박막의 성장과 광학적 특성

남성운,정양준 木浦大學校基礎科學硏究所 1997 基礎科學硏究誌 Vol.15 No.-

ZnTe epilayer of high quality was grown on GaAs substrate by hot wall epitaxy(HWE) methods. The atomic ratio of Zn : Te in the epilayers was found to be almost 1:1 by Rutherford Backscattering Spectrometry(RBS). The best value of the full width at half maximum(FWHM) of the double crystal rocking curve(DCRC) of ZnTe epilayer was obtained 93 arcsec. The PL spectrum with the strong free exciton peaks and no oxygen-bound exciton peaks showed the high quality of the films. From the splitting of the heavy hole and light hole band, the tenslie strain was identified. With the excitation source of 514.5 nm Ar-ion laser, three resonant Raman lines were observed.

LP-MOCVD 방법으로 성장한 InGa As/GaAs의 DCXD에 의한 조성과 임계두께에 관한 연구

정양준,차상석,임기영 木浦大學校 基礎科學硏究所 1994 基礎科學硏究誌 Vol.12 No.-

We have grown InGaAs single layers on GaAs by LP-MOCVD(Low Pressure Metal-Organic Chemical Vapor Deposition) method. We have investigated the lattice constants, strain relaxation, and critical layer thickness of a ?? layer by double crystal x-ray diffraction. The correlation between the In composition in epitaxial ?? and In gas composition was determined by rocking curve analyses. The critical layer thickness and In composition were determined to be 600Å for 0.115 and 400 Å for 0.183, respectively, assuming that the In gas compositions are 0.150 and 0.243. Beyond the critical layer thickness the transition from the strained to the relaxed state occurs more rapidly as the thickness increases.

??의 전기전도 특성 및 에너지 밴드구조

정양준,박문규,이형재 木浦大學校基礎科學硏究所 1988 基礎科學硏究誌 Vol.6 No.-

Experimental measurement of electrical conductivity and Hall coefficient have been made as a function of temperature on n-type five ?? alloys which had as component ratio of 0.02, 0.11, 0.21, 0.275, 0.32 respectively. Theorical calculation of electrical conductivity and Hall coefficient have been made on a three band model using the method of Fletcher and Butcher and the resulting values fitted to the experimental measured data. Where unknown parameters were energy of L₁and X₁band edge, and the compensated acceptor density. The resulting analysis show the band gap variation given by ?? and ?? at room temperature. Various scattering mechanisms are also discussed in this work.

InSb의 결정성장 및 특성

정양준,양순철,이형재 木浦大學校基礎科學硏究所 1989 基礎科學硏究誌 Vol.7 No.-

InSb crystals, both doped and undoped, were grown using the zone-refining technique in vacuum. The unintentionally doped crystals exhibit n-type conduction with the lowest carrier concentration of ??. The pure crystals show intrinsic characteristics even at very low temperatures. Hence very heavily doped n-type crystals were grown in an effort to determine the electron behaviors, not disturbed by the other bands over a wide temperature range. All the InSb crystals prepared in this work were self-seeded along the (111) direction, and the volatilization turned out to be very efficient in reducing the residual impurities during the growing process. The electrical conductivity and Hall coefficient were measured as a function of temperature from 90 to 570K. Theoretical calculations were carried out using a three-band model with the ?? and two hole bands taking into account scattering mehanisms. The results were consistently fitted to the experimental data with the adjustable parameters used in describing the temperature variation of band gap, heavy hole effective mass??, deformation potential??. The final fitting was obtained with the following values, ??, ??, ??. At high temperatures polar optical scattering is dominant for electron scattering and electron-hole scattering becomes very important.

p-형 GaAs 의 실온특성

정양준,이형재 木浦大學校基礎科學硏究所 1985 基礎科學硏究誌 Vol.3 No.-

Electrical transport properties of p-type GaAs were examined using Fermi energy and ionized impurity density as variables in this work. At 297K the heavy and light hole bands were taken into consideration with the use of two-band model. We assumed parabolic and nonparabolic forms for heavy and light hole bands, respectively, and spherical constant-energy surfaces for both bands, respectively, and spherical constant-energy surfaces for both bands. Fletcher and Butcher method modified was employed for the calculation of Boltzmann equation, and resultant analysis may be used as a tool in assessing p-type GaAs at room temperature.

Band Structure and Electrical Transport in InAs

Jung, Yang-June,Kim, Byung-Ho,Lee, Hyung-Jae,Woolley, John C 全北大學校 1981 論文集 Vol.23 No.-

실온에서 2.7×10^22와 4.5×10^22m^-3 사이의 전자밀도를 갖는 6가지의 n-형 InAs 결정 반도체에 대해서 Hall 계수와 전기전도도를 온도의 함수로 측정했고, 1.5×10^22와 3.8×10^22m^-3의 전자밀도를 갖는 다른 두개의 시료에 대해서는 전기저항과 Hall 계수를 압력의 함수로 측정했다. Γ_lc와 두 개의 hole band를 고려하는 model을 본 이론에 도입했고, 여러 가지 산란이론을 이용해서 계산한 이론치를 실험결과에 일치시킴으로써 high-frequency dielectric constant κ_∞, Γ_lc와 heavy hole band에서의 deformational potential E_DP 및 E_DH 그리고 energy gap의 압력변화 계수 α_p를 구했다. 본 연구에 의하면 Γ_lc에서는 polar optical phonon에 의한 산란이, 그리고 heavy hole band에서는 nonpolar optical phonon에 의한 산란이 가장 중요한 것으로 나타났으며 100℃ 이하에서는 Γ_lc band만으로 실험결과를 설명할 수 있었다. 실온에서부터 270℃까지의 본 실험온도 영역에서 light hole band는 무시가 되며 heavy hole은 100℃ 이상의 온도에서 Γ_lc band로 전자가 여기되고 전자에 대해서 산란중심을 제공하므로 중요하게 다루어진다. 그러나 heavy hole band 자체에서의 수송현상은 실험결과를 설명하는데 역시 중요치는 않다. 본 연구에서 얻은 parameter 값은 아래와 같다. 즉, κ_∞ = 12.37, α_p = 1.14×10^-2 eV/kbar, E_DP = 13.6 eV, E_DH = 4.0 eV