1- To dope Ge with n- and p-type doping, which materials should be used (a) Al f
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Question
1- To dope Ge with n- and p-type doping, which materials should be used
(a) Al for p-type
(b) In for n-type
(c) C for n-type
(d) As for p-type
(e) Sb for n-type.
2- To dope GaAs with n- and p-type doping, which materials should be used
(f) Al for p-type
(g) In for n-type
(h) C for n-type
(i) As for p-type
(j) Sb for n-type.
3- To dope ZnSe with n- and p-type doping, which materials should be used
(k) Al for p-type
(l) In for n-type
(m) C for n-type
(n) As for p-type
(o) Sb for n-type.
Explanation / Answer
1) The Ge as per periodic table it is a Germanium and belogs to Group IV means it has four valence electrons so the characteristics of this group is same to all elements will have 4 valence electrons in outer most orbit.
Now for to dope n-type doping for Germanium we need pentavalent element (i.e Group V elements) to dope with Germanium because pentavalent combined with Ge and has a excess electron in its orbit forming n-type semi conductor and in other case to dope p-type for Ge we need trivalent element(i.e Group III elements) to dope with Germanium because trivalent occupies 3 valence electrons of Ge and the fourth elements form a hole making semiconductor as a P type .
Group V elements are Nitrogen(Ni),Phosporous(p),Arsenic(As),Antimony(Sb),Bismuth(Bi) for N-Type
Group III elements are Boron(B), aluminium(Al),gallium(Ga) ,indium(In) and thalium(Ti) for P-Type
From given Options the
(a) Aluminium(Al) is used for P type
(b) Indium(In) is Not used as N type as it is Group III element used for P type
(c) Carbon(c) is group IV element it is not used for any type of doping for Ge.
(d) Arsenic(As) is not used for P-type it is used for N-type.
(e) Antimony(Sb) is used for N-type.
2) GaAs is Combination of Ga and As where Ga is Group III element consisiting valence 3 and As is Group V element consisting of 5 valence electrons this two combination will form a 4 valence electron Per GaAs atom.
The Answer to Dope the GaAs Crystal is to replace Group V elements with Group IV to Form N Type i.e Carbon(C),Silicon(Si) and Germanium(Ge) which occupies Ga sites in GaAs crystal and form a Donar in the atom .
among (f),(g),(h),(i) and (j) only (h) C can be used for N-type remaining cant be used for doping as they first two belongs group III and last two belongs to Group V.
3) Znse it is Zinc selenide consists the combination of Group 12 (II) and Group 16(VI) in periodic table.
For Doping P Type For ZnSe is done by Group V elements such as N,P,As,Sb
so (n) As is used for P-type and remaining or not correct and not used for N-type Halogen may be used for Znse
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