1.Explain two types of defects created in crystalline ionic solida (1)Schottky defects and (2)Frenkel defects.(10) [solution] Schottky defect: 是晶體結構中的一種因原子或離子離開原來所在的格點位 置而形成的空位式的點缺陷。在離子晶體中，各種離子形成的肖特基缺陷數 目符合晶體的元素構成比例，因為只有這樣形成缺陷後的晶體才是電中性的。 Frenkel defect: 是指晶體結構中由於原先佔據一個格點的原子（或離子）離 開格點位置，成為間隙原子（或離子），並在其原先佔據的格點處留下一個空 位，這樣的空位-間隙對就稱為弗侖克爾缺陷。 2.(習題57題)The band gap in aluminum phosphide(AlP) is 2.5 electron-volts(the charge of electon is 1.6*10^-19 Coulomb). What wavelength of light is emitted by an AlP diode?(10) 3.(習題51題)A. Use the band model to explain how conductors and seminconductors differ as to the effect of temperature on electrical conductivity.(10) B. Using silicon seminconductors as a model, define the n-type and p-type seminconductors.(10) 10.The standard enthalpy of combustion of cyclopropane is -2091 KJ/mol. The standard enthalpy of formation for CO2(g) and H2O(l) is -393.51 and -285.83 KJ/mol, respectively. Calculate the enthalpy of formation of cyclopropane to be (a)53KJ/mol,(b)42KJ/mol,(c)102KJ/mol,(d)33KJ/mol,(e)none of above 16.Diesel fuel normally uses petroleum of (a)C5-C10,(b)C10-C18,(c)C15-C25,(d) >C25,(e)cannot be determined 1.Li(s) → Li(g) heat of sublimation of Li(s)=166 KJ/mol HCl(g) → H(g) + Cl(g) bond energy of HCl=427 KJ/mol Li(g) → Li(g)+ + e- ionization energy of Li(g)=520 KJ/mol Cl(g) + e- → Cl-(g) electron affinity of Cl=-349 KJ/mol Li(g)+ + Cl-(g) → LiCl(s) lattice energy of LiCl(s)=-829 KJ/mol H2(g) → 2H(g) bond energy of H2(g)=432 KJ/mol Calculate the net change in energy for the reaction: 2Li(g) + 2HCl(g) → 2LiCl(s) + H2(g) a)363 KJ b)-562 KJ c)-179 KJ d)-73 KJ e)non of above e.n-type and p-type of semiconductors.(5%) What type of semiconductor would be formed if a small amount of Selenium impurity were added to pure Arsenic? 3.For a given volume, which of the following shapes has the smallest surface (a)cube (b)tetrahedron (c)pyramid (d)octahedral (e)sphere 4.Which method may generally decrease the conductivity of a semiconductor (a)decreasing the temperature (b)adding an impurity (c)irradiating with (d)decreasing the energy gap (e)none of tghe answers 11. describe the free electron model (classical model) and quantum mechanical model for the metal conductivity (5). What is the drawback(缺點) of the classical model?(5) 12. (a) Using the band gap theory to explain the semiconductor, (b)p-type semiconductor, (c) n-type semiconductor. (3 points each) B-3. (習題 chapter 16-51 衍生) (a)Using the band gap theory to explain the insulator, conductor, semiconductor, p-type semiconductor and n-type semmiconductor. (10) (b)Upon increasing temperature, predict the trend of conductivity (increase of decreade) of conductor and semiconductor.Explain. (5) sol> 圖略 如果幾個原子集合成分子，這會產生與原子數量成比例的分子軌道。當大量 （數量級為10^20或更多）的原子集合成固體時，軌道數量急劇增多，軌道相互 間的能量的差別變的非常小。形成所謂的band。 物質的導電性決定於價帶與傳導帶之間的能量差，也就是所謂的band gap。 band gap越小則導電性越大。金屬沒有band gap；半導體的band gap大約為 1.1 eV；絕緣體則有相當大的band gap。 (p-type 和 n-type 從略) 金屬的導電性隨著溫度上升而下降，因為溫度的上升會導致金屬陽離子振動的增 加，阻礙自由電子的運動。在半導體中，溫度的上升導致一些電子從價帶被激發 到傳導帶，使得價帶中有電洞而傳導帶中有自由電子，因此導電性上升。 13. Based on the p-n junction, describing the photovoltaic cell.(3) B-1-4. What does state function mean? (5) Which of the following functions are state functions:(a)PV work,(b)heat,(c)entropy,(d)free energy (e)electrical work. (5) B-2. Silver crystallizes in a cubic closest packed structure shown below.The radius of a silver atom is 1.44埃, calculate the density of solid silver.(molecular weight of silver = 107.9 g/mol) (10) ( 圖為一cubic closest packed structure ) sol> Mass 4×107.9(g/mol)/(6.02×10^23)(1/mol) D = ──── = ────────────────── = 10.6 g/cm^3 Volume [4(1.44×10^(-8))(cm)/√(2)]^3 B-1-2. First, Second and Third law of thermodynamics. (5) sol> First: 能量在各型式間轉換時不滅 Second: 系統所吸收的熱無法完全轉換為功, or 自發反應的發生必伴隨著亂度的增加 Third: 完美晶體在絕對零度時的亂度為0 1-5 Explain why the molar heat capacity (Cv) of most mono atomic metal is ~3R at room temperature (Pierre-Louis Dulong and Alexis-Therese Petit rule), while Cv is ~0 when temperature is close to 0 K.(5) B1-1.Using the band gap theory to explain the "conductor", "semiconductor", "p- type conductor", "n-type conductor". (10) B-1-4. What does state function mean? [sol]State function: 處於平衡態的熱力學系統，各宏觀物理量具有確定的值，並 且這些物理量僅由系統所處的狀態所決定，與達到平衡態的過程無關，因此被 稱之為狀態函數。 B1-7. What does state function mean?(5) Which of the following functions are state functions (複選, multiple choices): (a) work, (b) internal energy, (c) heat, (d) temperature, (e) gravitational potential, (f) free energy, (g) f(x,y)=xy+6x2+y^2-2x+3y (5) B2. Cubic packing spheres are stacked on top of each other in successive layers. Define volume occupied by spheres in the unit cell f_v = ─────────────────────── volume of the unit cell prove f_v = 52.4% for a cubic packing.(10) 上面都是冗ㄐㄐㄐㄐㄐㄐㄐㄐㄐㄐㄐ在九如冗時收集的考古題 可能會在下次的小考出現~ --

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