To reveal the complicated mechanism of the multicomponent mass transfer during the growth of ternary compound semiconductors, a numerical model based on Maxwell-Stefan equations was developed to simulate the Bridgman ...To reveal the complicated mechanism of the multicomponent mass transfer during the growth of ternary compound semiconductors, a numerical model based on Maxwell-Stefan equations was developed to simulate the Bridgman growth of CdZnTe crystal. The Maxwell-Stefan diffusion coefficients in the melt were estimated. Distributions of Zn, Cd, and Te were calculated with variable ampoule traveling rate and diffusion coefficients. The experimental results show that Zn in melt near the growth interface decreases and diffuses from the bulk melt to the growth interface. For Cd, the situation is just the opposite. The coupling effects of Zn and Cd diffusions result in an uphill diffusion of Te at the beginning of the growth. Throughout the growth, the concentration of Te in the melt keeps low near the growth interface but high far from the growth interface. Increasing the ampoule traveling rate will aggravate the segregation of Zn and Cd, and hence deteriorate the uniformity of Te. We also find that not only the diffusion coefficients but also the ratios between them have significant influence on the species diffusions.展开更多
To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am （5.48 MeV） radioactive sour...To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am （5.48 MeV） radioactive source at room temperature. The electron mobility lifetime products （μτ）e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with （μτ）e = 2.3 × 10？3 cm2/V and μe =1000 cm2/（V·s）, respectively, exhibits an excellent γ-ray spectral resolution of 6.4% （FWHM = 3.8 keV） for an un-collimated 241Am @ 59.54 keV isotope.展开更多
A simple method of carbon film coating used in CdZnTe crystal growth was developed. The optimum parameters were selected. Breakdown of carbon film was commonly seen if Cd reservoir was not used in the crystal growth. ...A simple method of carbon film coating used in CdZnTe crystal growth was developed. The optimum parameters were selected. Breakdown of carbon film was commonly seen if Cd reservoir was not used in the crystal growth. The carbon film was in good condition when the vapor pressure of Cd was kept around 0.1 MPa during crystal growth.展开更多
基金Funded by the National Key R&D Program of China(2016YFB0402405,2016YFF0101301)the Special Fund of National Key Scientific Instruments and Equipments Development(2011YQ040082)+4 种基金the National 973 Project of China(2011CB610400)the 111 Project of China(B08040)the National Natural Science Foundation of China(NNSFC-61274081,51372205,and 51502244)the Fundamental Research Funds for the Central Universities(3102015BJ(II)ZS014,G2016KY0104,3102016ZY011)the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China
文摘To reveal the complicated mechanism of the multicomponent mass transfer during the growth of ternary compound semiconductors, a numerical model based on Maxwell-Stefan equations was developed to simulate the Bridgman growth of CdZnTe crystal. The Maxwell-Stefan diffusion coefficients in the melt were estimated. Distributions of Zn, Cd, and Te were calculated with variable ampoule traveling rate and diffusion coefficients. The experimental results show that Zn in melt near the growth interface decreases and diffuses from the bulk melt to the growth interface. For Cd, the situation is just the opposite. The coupling effects of Zn and Cd diffusions result in an uphill diffusion of Te at the beginning of the growth. Throughout the growth, the concentration of Te in the melt keeps low near the growth interface but high far from the growth interface. Increasing the ampoule traveling rate will aggravate the segregation of Zn and Cd, and hence deteriorate the uniformity of Te. We also find that not only the diffusion coefficients but also the ratios between them have significant influence on the species diffusions.
文摘To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am （5.48 MeV） radioactive source at room temperature. The electron mobility lifetime products （μτ）e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with （μτ）e = 2.3 × 10？3 cm2/V and μe =1000 cm2/（V·s）, respectively, exhibits an excellent γ-ray spectral resolution of 6.4% （FWHM = 3.8 keV） for an un-collimated 241Am @ 59.54 keV isotope.
文摘A simple method of carbon film coating used in CdZnTe crystal growth was developed. The optimum parameters were selected. Breakdown of carbon film was commonly seen if Cd reservoir was not used in the crystal growth. The carbon film was in good condition when the vapor pressure of Cd was kept around 0.1 MPa during crystal growth.
