| 24小時(shí)熱門(mén)版塊排行榜 |
| 5 | 1/1 | 返回列表 |
| 查看: 1410 | 回復(fù): 10 | |||
| 本帖產(chǎn)生 1 個(gè) 翻譯EPI ,點(diǎn)擊這里進(jìn)行查看 | |||
| 當(dāng)前只顯示滿足指定條件的回帖,點(diǎn)擊這里查看本話題的所有回帖 | |||
[交流]
翻譯求助
|
|||
|
各位大蝦幫忙翻譯一下,急!謝謝! It is interesting to consider the phase diagram that results if we exclude the Ta5N6 phase (e.g., if it is prevented from forming due to particular experimental conditions). The result is shown in Fig. 4(d). In this case, in addition to the Ta2N and Ta3N5 phases, which are now favorable over a larger region, the Ta4N5 structure appears in a relatively wide range of ( μN(yùn),μTa)phase space and, in addition, a structure containing N vacancies in a rocksalt lattice is seen (rs-Ta4N3). It can be noticed that when sweeping from right to left in the phase diagram and going from high μN(yùn), low μTa to more low μN(yùn), high μTa conditions, the Ta to N ratio increases;namely, it changes from 0.6 (Ta3N5) to 0.8 (Ta4N5) to 1.33 (rs-Ta4N3) to 2.0 (Ta2N); that is, the phases change from so-called “higher nitrides” to “l(fā)ower nitrides.” This is similar to the trend found in Ref. 2 when heating the Ta3N5 phase under UHV as described in the Introduction, which causes desorption and loss of N atoms as N2, resulting in progressively more Ta-rich materials. In Figs. 4(c)and 4(d), the scale of the N chemical potential is correlated with the N2 pressure for two selected temperatures [cf. Eq. (2)]. At 600 K, it can be seen from Fig. 4(c) that for pressure ranges used in industry and laboratories—i.e., from ultrahigh vacuum to 100 atm (10−15~100 atm or 0.65×10−12–0.65×105 Torr), which correspond to mN in the range of ,−0.4 to ,−1.4 eV, the Ta5N6 phase is the most stable. This is also the case at 1000 K even though the corresponding range of μN(yùn) is shifted and considerably extended(~-0.8 to ~−2.4 eV). Considering Fig. 4(d), however,which contains the metastable N-vacancy structure(rs-Ta4N3) and Ta4N5 phase, it can be seen that at 600 K,Ta4N5 is favored, while at 1000 K, depending on the pressure,either Ta4N5, rs-Ta4N3, or even Ta2N may be favored.Thus, through variation of the temperature and pressure, different structures become energetically favored, and in general, structures with higher N contents are predicted for higher N2 pressures, while for a given pressure, higher temperatures are predicted to give rise to more N-deficient structures.This is in qualitative agreement with the experimental results. In summary, through highly precise total energy FLAPW calculations we studied the relative stability and associated electronic properties of stable and metastable structures of the Ta-N system. In all cases, the calculated equilibrium volume is in excellent agreement with experiment. We find that there are three stable phases—namely, Ta2N, Ta5N6, and Ta3N5; the rest are metastable. The electronic properties range from strongly metallic (Ta2N) to more resistive(Ta5N6) and finally to insulating (Ta3N5). The very close energies calculated for the various structures investigated for certain regions of the phase diagram suggest that kinetic effects(due, e.g., to diffusion barriers for atomic rearrangement or epitaxial stabilization effects) will play an important role for this complex system and that the chemical and phase compositions of deposited films will depend critically on the growth conditions. This is in accordance with, and helps explain, the wide range of different structures observed experimentally. |
» 搶金幣啦!回帖就可以得到:
+2/386
+1/189
+1/91
+1/63
+1/33
+1/32
+1/18
+1/14
+1/14
+1/12
+1/8
+1/8
+1/7
+1/7
+1/7
+1/6
+1/4
+1/1
+1/1
+1/1
至尊木蟲(chóng) (職業(yè)作家)
|
In summary, through highly precise total energy FLAPW calculations we studied the relative stability and associated electronic properties of stable and metastable structures of the Ta-N system. In all cases, the calculated equilibrium volume is in excellent agreement with experiment. We find that there are three stable phases—namely, Ta2N, Ta5N6, and Ta3N5; the rest are metastable. The electronic properties range from strongly metallic (Ta2N) to more resistive(Ta5N6) and finally to insulating (Ta3N5). The very close energies calculated for the various structures investigated for certain regions of the phase diagram suggest that kinetic effects(due, e.g., to diffusion barriers for atomic rearrangement or epitaxial stabilization effects) will play an important role for this complex system and that the chemical and phase compositions of deposited films will depend critically on the growth conditions. This is in accordance with, and helps explain, the wide range of different structures observed experimentally. 總之,通過(guò)高度精確的總能FLAPW方法計(jì)算,我們研究了Ta- N系統(tǒng)的穩(wěn)態(tài)和亞穩(wěn)態(tài)結(jié)構(gòu)的相對(duì)穩(wěn)定性和相關(guān)的電學(xué)特性。在所有情況下,計(jì)算出的平衡量與實(shí)驗(yàn)符合較好。我們發(fā)現(xiàn),有三種穩(wěn)定的階段,即Ta2N、Ta5N6和Ta3N5,其余的是亞穩(wěn)態(tài)。電學(xué)性質(zhì)的范圍從強(qiáng)烈的金屬性(Ta2N),到電阻性(Ta5N6),最后以絕緣(Ta3N5)結(jié)束。為研究相圖的某些區(qū)域的各種結(jié)構(gòu)能量計(jì)算表明,動(dòng)力學(xué)效應(yīng)(因?yàn)椋,由于原子排列造成的擴(kuò)散障礙或外延穩(wěn)定效應(yīng))將在這個(gè)復(fù)雜體系發(fā)揮重要作用,沉積薄膜的化學(xué)和相組成將嚴(yán)格地取決于生長(zhǎng)條件。這與實(shí)驗(yàn)中觀測(cè)到寬范圍的不同結(jié)構(gòu)一致,并有助于解釋實(shí)驗(yàn)結(jié)果。 |
至尊木蟲(chóng) (職業(yè)作家)
|
It is interesting to consider the phase diagram that results if we exclude the Ta5N6 phase (e.g., if it is prevented from forming due to particular experimental conditions). The result is shown in Fig. 4(d). In this case, in addition to the Ta2N and Ta3N5 phases, which are now favorable over a larger region, the Ta4N5 structure appears in a relatively wide range of ( μN(yùn),μTa)phase space and, in addition, a structure containing N vacancies in a rocksalt lattice is seen (rs-Ta4N3). It can be noticed that when sweeping from right to left in the phase diagram and going from high μN(yùn), low μTa to more low μN(yùn), high μTa conditions, the Ta to N ratio increases;namely, it changes from 0.6 (Ta3N5) to 0.8 (Ta4N5)to 1.33 (rs-Ta4N3) to 2.0 (Ta2N); that is, the phases change from so-called “higher nitrides” to “l(fā)ower nitrides.” This is similar to the trend found in Ref. 2 when heating the Ta3N5 phase under UHV as described in the Introduction, which causes desorption and loss of N atoms as N2, resulting in progressively more Ta-rich materials. 如果我們排除Ta5N6階段(例如,如果由于特定的實(shí)驗(yàn)條件未能形成),考慮得到的相圖將很有趣。結(jié)果如圖4(d)所示。在這種情況下,除了目前已在更大區(qū)域有利的Ta2N和Ta3N5階段,Ta4N5結(jié)構(gòu)出現(xiàn)在一個(gè)比較寬的范圍(μN(yùn),μTa)相空間,此外,可以看到一個(gè)包含了N空位是巖鹽格結(jié)構(gòu)(rs - Ta4N3)?梢宰⒁獾剑(dāng)由右至左清掃相圖,由高μN(yùn)、低μTa,到更低μN(yùn)、高μTa條件, Ta /N比增加,從0.6(Ta3N5)至0.8 (Ta4N5)至1.33(rs - Ta4N3)至2.0(Ta2N)改變,也就是說(shuō),相變是從所謂的“高氮化物”到“低氮化物”,變化趨勢(shì)與在參考文獻(xiàn)2發(fā)現(xiàn)的類似,如引言中所述,特高壓下加熱的Ta3N5相,這將導(dǎo)致脫附和氮原子以N2形式損耗,造成富Ta材料的逐步形成。 |
至尊木蟲(chóng) (職業(yè)作家)
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|