CAJ | 학술논문

采用定向凝固的方法，在一定的氢压条件下制备具有长孔结构的藕状多孔Si。通过调整凝固速率和氢气压力，铸锭的孔隙率、孔径和孔长度能够得到有效控制。实验结果表明：当其他条件不变时，铸锭的面孔隙率几乎不随凝固速率发生变化，但随着氢气压力的增加而逐渐降低。采用理论模型获得的不同氢压条件下制备出的铸锭体孔隙率预测结果与实验结果吻合较好。随着凝固速率和氢气压力的降低，铸锭的平均孔长度和孔径均逐渐增加，长径比则基本保持不变。通过将熔体的过热度从200 K提高到300 K，制备得到的试样其平均孔径增加约0.3 mm，平均孔长度从7 mm提高至24 mm，平均长径比则由8提高至20。
채용정향응고적방법，재일정적경압조건하제비구유장공결구적우상다공Si。통과조정응고속솔화경기압력，주정적공극솔、공경화공장도능구득도유효공제。실험결과표명：당기타조건불변시，주정적면공극솔궤호불수응고속솔발생변화，단수착경기압력적증가이축점강저。채용이론모형획득적불동경압조건하제비출적주정체공극솔예측결과여실험결과문합교호。수착응고속솔화경기압력적강저，주정적평균공장도화공경균축점증가，장경비칙기본보지불변。통과장용체적과열도종200 K제고도300 K，제비득도적시양기평균공경증가약0.3 mm，평균공장도종7 mm제고지24 mm，평균장경비칙유8제고지20。
Lotus-type porous silicon with elongated pores was fabricated by unidirectional solidification under pressurized hydrogen. Porosity, pore diameter, and pore length can be adjusted by changing solidification speed and hydrogen pressure. The porosity of the ingot is nearly constant under different solidification speeds, but decreases with the increase of hydrogen pressure. The overall porosities of ingots fabricated at different hydrogen pressures were evaluated through a theoretical model. Findings are in good agreement with experimental values. The average pore diameter and pore length increase simultaneously while the average pore aspect ratio changes slightly with the decreases of solidification speed and hydrogen pressure. The average pore length is raised from 7 to 24 mm and the pore aspect ratio is raised from 8 to 20 respectively with the average pore diameter promoted by about 0.3 mm through improving the superheat degree of the melt from 200 to 300 K.