Chế tạo và khảo sát vật liệu bán dẫn p zno

Dai hoc Quoc gia Ha noi Tniofng Dai hoc Khoa hoc Tit nhien _ TfeND^TAI: CHf TAO VA K H A O SAT VAT LifiU BAN D A N P-ZnO MA Sd: QT- 08-11 CHU TRI Di TAI: TS NGO THU HUONG (KHOA V^T L^) Ha noi - 2008 Dai hoc Quoc gia Ha noi Trtfcmg Dai hoc Khoa hoc Tii nhien >v' V TEN DE TAI: V CHE TAO VA KHAO SAT VAT LIEU BAN DAN P-ZnO MA SO: QT- 08-11 CHU TRI f)t TAI: TS NGO THU HUONG (KHOA VAT LY) ^'^\;;ic- T,-,t DT/ qo4 Ha noi - 2008 Dai hoc Quoc gia Ha noi Triiomg Dai hoc Khoa hoc Tii nhien TEN DE T A I : CHE TAO VA K H A O S A T V A T L I E U B A N D A N P-ZnO MA SO: QT- 08 -11 CHU TRI DE TAI: TS NGO THU HUONG CAC CAN B O T H A M GIA: TSKH NGUYfiN HOA HONG NCS NGUYilN VIET TUYEN SINH VIEN: CHU THI THU Ha noi - 2008 Bao cao torn tat a Ten de tai : Che tao va khao sal vat lieu ban dSn p-ZnO (Mas6:QT-08-ll) b Chu tri de tai: TS Ngo Thu Hacmg c Cac can bo tham gia: TSKH Nguyin Hoa Hong NCS Nguyin Viet Tuyen Sinh vien: Chu Thi Thu d Thoi gian thuc hien tuf thang 01 nam 2008 den thang 12 nam 2008 e Muc tieu va noi dung nghien ciru: Che tao vat lieu ban din loai p-ZnO va nghien cuii cac tinh chat cau triic, tinh chat nhiet, dien va quang cua loai vat lieu f Cac ket qua dat dupe: Ket qua cua di tai bao gom 01 bai bao giri dang tap chi cua Dai hoc quoc gia Ha noi; 01 bai hsioa'^gxxi dang lap chi nirorc ngoai; tham gia hucfng dSn 01 sinh vien nghien curu khoa hoc, se bao ve nam 2009; tham gia hudng din 01 nghien cun sinh g Tinh hinh kinh phi cua d6 tai: Tong kinh phi ihuc chi: 20.000.000 dong Trong - Tir ngan sach nha nu6c: 20.000.000 d6ng - Vay tin dung: - Von tuco: Khoa quan ly (Ky va ghi ro ho ten) Chu tri de tai (Ky va ghi ro ho ten) IM^ ly de tai 9H6 WEU TRU /- oF: A V \ -r ; f I V\ M L , ; i" 1,1 i / )3^i6%^^^'^ Brief project report a Project title: Preparing and studying semiconductor p-type ZnO materials (QT-08 - 11) b Project co-ordinator: Dr Ngo Thu Huong c Co-operalor: Dr Nguyen Hoa Hong Ph.D student Nguyen Viet Tuyen Student Chu Thi Thu d Duration: from 2008, January to 2008, December) e Objectives and scientific contents: The main object of this project is: preparing the p-type ZnO material and studying the structural, electrical and optical properties of this material f Results: The main results of this work were given in the scientific paper in the VNU Jounal of Science, Mathematics - Physics, 12/2008.; 01 paper to be submit in international journal Supervisor one research student and one Ph.D student g Budget: 20.000.000 VND Mucluc Trang T6ng quan v^ vai lieu C4c phuong phip thuc nghifim 10 Cac k6i qua va bien luan 11 K^tluto 16 Tki lieu tham khao 16 Phin 1: T^ng quan ve vat lieu Viec |Aa tap c4c tap acceptor d^ thu duoc vat heu ban din p - ZnO \k mdt vSn d6 duoc dat cin phai giai quy€t viec img dung cdc hnh kien b^n din nky D^ thu dupe bdn dSn loai p, thu5ng cac nguyen 16' nh6m V nhu N, P, As dupe d&ng nhi^u [1-5] Tuy nhien, nhom nguyen 16' Cu, Ag viec thay v^o vi iri Zn cung thu dupe bdn d ^ loai p Cu dupe diing nhu c^c acceptor 6i thay v^o vi tri ciia Zn v) bin kinh cua ion Qi^ la 0,098 nm va Cu^^ la 0,080 nm la gin nhu tuong duong vdi bdn kinh ciia ion Zn^^ (0,083 nm) Viec c^c nguyen l6 Ihupc nh6m V Ihay the' Zn anh hucmg ro ret len cdc tinh ch^t dien v^ quang cua vat lieu bin din Vi the' d6 tii niy chung t6i nghien cihi su anh hudng cua phospho len cac tinh cha^t ciu true cua vat lieu bdn din loai p-ZnO 1.1 Tinh chit can true cua vat lieu ZnO Til ca cic vai lieu thu6c nh6m II-VI d^u c6 du true cubic hoac du true luc giic Wurtzite Vat lieu ZnO Ihucmg t6n lai m6t ba dang nhu dupe chi iren hinh I Rocksah(Bl) Zinc blende (B3) Wurtzite (B4) Hinh 1; Qfu true ciia ZnO: (a) dang cubic rocksalt, (b) dang Zinc blende v^ (c) dang Wutzite 12 Ciu true vdng ndng liromg cua vat lieu ZnO: Hinh chi ph6 phit xa cua nang lupng photon dai lijr 20 de'n 50 eV vi cic th6ng sd ciia khd'i ciu true vung nang lupng ciia vai heu ZnO Trong cac ph^p niy, cic b6 nang lupng lien quan tdi mirc nang lupng Fermi va cu5ng dp thdng qua th6ng lupng cua photon E,=0 (a) 12 12 Binding energy (eV) Hmh 2: (a) ph6 phat xa cua nSng lupng photon dai lir 20-50 eV (b) C^u true vilng cua ZnO Hinh la c^u true vung nang lupng theo tinh loan ly thuye't va t6ng cac mat dp Irang Ih^ (DOS) vdfi cdc pha khac ciia ZnO Khi c^u true wurtzite hi xam pham, c6 th^ nhan tha'y rang edc peak a dinh ciia viinghoa tri iren giam kh6ng dang k^ v£ 66 cao 20 15 10 10 "•*"^ $ ^"^^s^^^ ? -10 • M2II0 -16 -20 -10 -20 M 1r \ (b) A Hinh 3: Qfu true vung cua ZnO (a) d\i true B4 p = 0; (b) e^u true B, a p = pr, va (c) c§^u true B2 cf p = Pr2 1.2 Tinh chat dien cua vat lieu ZnO: vat lieu ZnO la vat lieu ban din vung cam rpng va th^ng do chung la vat lieu c6 nhien kha nang umg dung quang hoc va dien hoc Khi nghien curu tinh ch^t dien ciia vat lieu ZnO, nhien nhom nghien cum da nghien cihi sur hinh ban dan loai p pha tap va tim cac bien phap de khac phuc sachuyen ttr ban dan loai p sang ban dan loai n Hinh 1.4 la su phu thupc nhiet dp ciia hang so Hall va nong dp cac phan tiir tai cua ban dan ZnO (theo tinh toan ly thuye't va thuc nghiem) Trong hinh 1.4, b khoang nhiet dp 15 K < T < 40 K thi tinh chat van chuyen ciia no bao gom to hpp cac vung va dp dan qua lai Khi nhiet dp dat 50 K, hdng so Hall dat cue dai 2000 cmVVs sau giam nhanh nhiet dp tdng 2000 A 1 1 T' " - ' Bulk ZnO /o ^p 1S00 "3* \o 1000 V Theory o \i *v^ 500 o •o ^*^*^^**^ t I 100 200 T(K) I 300 40C Hinh 4: Su phu thupe nhiet dp ciia hang s6 Hall ciia mSu ZnO khoi (hinh tron la di^m thuc nghiem, dudng liln n^t la du6ng \f thuye't) Hinh 1.5 la su phu thupc ciia nong dp cac phan tii tai vao 1000/T ciia ban dan ZnO (theo tinh toSn ly thuye't va thuc nghiem) N6ng dd phin tur tii giam tuye'n tinh tilr 10'^ (cm ^) xuong lO^'* (cm^) va kha khdrp giOa duilmg tinh toan va duorng thuc nghiem I I I I I I I I I I I I I I I I Bulk ZnO Theory 10" r 10 15 lO^rr (K') Hinh 5: Su phu thu^ ciia n6iig dd cic phin tur tai v^o lOOO/T ciia bin din ZnO (theo tinh toan 1^ thuye't va thuc nghiem) However, there is a big problem is that how to make those samples durable that can stand over time without being aged and changing quality Normally for example N or P can be " put" into the ZnO (possible, even if it is also hard), but once they can get in then they also could go "out" again ^ The problem how to keep those dopants incorporated in a correct way so that they could be maintained inside the structure of ZnO should be a big problem to solve However, in reality, so far no one has achieved doing so In this paper, we report on the fabrications and investigation of structural properties of P-doped ZnO bulks and films made by evaporation effects Fnen though the p-type compounds that we have obtained are still not durable with lime, the fact that the samples could be made in nanometei-si/c and it could be controlled by deposition conditions/technique gives a hope that stabilized p-type / n O compounds could be well achieved in the future 11 Experiment Ceramic samples of Zni.^P.O (where A = 0.03; 0.06; 0.09 and 0.12) were prepared by a conventional solid-stale reaction method Appropriate icmperalures for calcinations and annealings were chosen for each compound based on results of Differential Scanning Calometry (DSC) and Thennal-gra\ imclric analysis (T(iA} measurements Samples were pressed inlo pellets under a pressure of Tern", and then annealed at 750, 900 and lOC'C for 10 hrs and ihey finally were cooled down slowly to room temperature As for film samples of Znj.xPxO (where x = 0.03; 0.06; 0.09 and 0.12) the powders of ZnO, P2O5 and 1% wt of C were well mixed then put into the middle of a tube furnace where the temperature, N2 pressure, and time of each annealing at each temperature could be well programmed The furnace was at first healed up at 1100"C for 30-60min Films were evaporated onto (111) Si substrates in the range of temperature from 600 to 700"C During the whole process of evaporation, the N: gas was continuously flown in order to protect the films from any oxidation Compositions of samples were checked by Hncrgy Dispcnsive Spectrum technique (EDS) The structural properties were investigated by X-ray diffraction (XRD) measurements perfonned by Siemens D5005 Scanning electron microscopy (SIvM) method by JHOL-JSM5410I.V Hall effect measurements were earned out at room temperature by Hall apparatus 7604, while Photoluminescence (PL) spectrum were detected by Fluorolog FL3-22 Jobin Yvon Spex USA III Results and Discussions Hall effect measurements that were perfonned at room temperature have shoun that the Zno.97Poo30 and Zno9jPo.o60 ceramic samples are/?-type semiconductors with hole concentration is of 10'\-ITI', while the Zno^iPoo^O and Zn(,ssP(ii:0 ceramic samples are 77-typc This seems to be understood if one sees their XRD paucms shown in Fig As for the samples with P concentration up to 0.06 only peaks of ZnO phase (with lattice parameters a h 3.756 A and c 5.028 A) are dominant and peaks of Zn^(POi);« arc ignorable (l-ig, (a)), while as for samples with P concentration larger than 0.06 the intensity of peaks of the alien phase of P is large (see peaks below 30^ pointed by some arrow in Fig (b)) It seems that a real incorporafion of P into the ZnO lattice as in the case of Znng/Po03O and Zno i^Poo^O samples is the main reason to be able to obtain thep-typc P-doped ZnO EDS data in Fig shows that P really got into ZnO (typical data for Znog/PotLiO) Data of other samples with different concentration of P dopant are presented in Table In fact when the concentration of dopant is little (such as 0.03), P can incorporate into the lattice much more easily (from the intensity of EDS spectrum for P, one can see clearly that when the P concentration is larger, the amount of P that indeed got into ZnO host lattice is smaller However, note that after few weeks, thep-typc characteristics of those samples is lost (most probably due to the instability of the incorporated P), since they have turned to be n-Xypc with electron concentration is about 1.2> Fig Huons et al 14 '-tr * X^f, • "(a) (b) ^i W -' (c) M f (d) Fig I luong el al 15 150 Q O 100 "b X = 0.12 X c x= 0.03 50 X = 0.09 X = 0.06 300 400 600 500 Wavelength (nm) Fig Huong el al Phieu dang ky ket qua nghien cuu KH-CN T6n de tai (ho$c du an): Che tao va khao sat vat lieu ban din p-ZnO Ma sd: QT-08-11 Co quan chu tri di tai (hoac dtr an): B6 mCn Vat ly Chat rdn - khoa Vat ly- DHKHTN Dia chi: 334 NguySn Trai - Thanh Xuan - Ha noi Tel: 8584069 Co quan quan ly de tai (hoac du an): Trudng Dai hoc Khoa hoc Tu nhien Dia chi: 334 Nguydn Trai - Thanh Xuan - Ha noi Tel: 8588579 Tdng kinh phi thtrc chi: Trong do: - Tir ngan sach Nha nude: 20.000.000 d - Vay tin dung: - Von tir CO: - Thu h6i: Thdi gian nghien curu: 01 nam Thcri gian bat d^u: 1/2008 Thcd gian ke't thuc: 12/ 2008 T6n cac can bp phoi hop nghien ciJu: TSKH Nguyen Hoa Hong NCS Nguyen Viet Tuyen Sinh vien: Chu TTii Thu S6' dang ky de tai Ngay: So chiing nhan dang ky ket qua nghien curu: 0 Bao mat: a Pho bien rong rai: [x] b Ph6 bien han che: c Bao mat: ^ Tom t^t k^t qua nghiSn cihi: Ndi dung chinh ma de tai dat duac la: Da che tao duac vat lieu ZnO pha tap phospho loai p va da khao sat cac tinh cha't ca'u true, tinh chat quang cua he vat lidu Ki^n nghi ve quy mo va doi tuong ap dung nghien cihi: De nghi dugc nghien cdu tie'p tuc d^ khao sat tinh cha't dien va quang cua vat lieu phu thuoc vao nhiet d6 Chu nhiem de tai Ho ten Ngo Thu Huong Thu truang ca quan chu tri de tai Chu tich Hoi dong danh gia chinh thurc Thu truang ca quan quan ly de tai Nguyen Hoang Luang Pham Quoc Trieu GS.TSKH PGS.TS TL.GIAMO6C tRUdNGBANWOAHOC CONC NGHC CSTSi^/^^^j^ ... Zn,. ,P, 0 (x = 0,03; 0,06; 0,09 va 0,12) dupe che tao bang hai phuofng phap: phucfng phap gom va phuong phap hoc bay nhiet mang N2 D6'i v6i he vat lieu kh6'i, h6n hpp cua bpt ZnO (99 %) va P2 O5... Zunger, Phys Rev B 63, 075205 (2001) Q.Wan Appl Phys Lett 89, 082515 (2006) FIGURE CAPTIONS XRD patterns for (a) Zno. r/PoojO and Zno. MP(i()f,0 and (b) Zun^iPoo^O and Zno. sxPo.iiO ceramic samples... As-doped p- type ZnO films prepared by cosputtering ZnO and Zn^Asi targets Journal of Crystal Growlh 307 (2007) 66 -69 [5] T.H Vlasenflin, M Tanaka, p- type conduction in ZnO dual-acceptor-doped