Chế tạo và khảo sát tính chất của lớp chuyển tiếp p n trên cơ sở màng mỏng zno và khả năng ứng dụng của chúng

DAI HOC QUdc GIA HA NOI TRUdNG DAI HOC KHOA HOC TU NHI^N ã ã ã ô ã ã ã CHE TAO VA KHAO SAT TINH CHAT CUA LOP CHUY^N TI^P p-n TREN CO SO MANG M N G ZnO VA KHA NANG U N G DUNG CUA CHUNG M a so: Q T - 08 - 16 CHU TRI D £ TAI: PGS TS Ta Dinh Canh CAC CAN BO THAM GIA: CN Nguyin Viet Tuyen HA N I - 2008 BAO CAO TOM TAT De tai: CHE TAG VA KHAO SAl TJNH CHAT CUA LQP CHUY^N TI^P p-n TREN CO Sd M A N G M N G ZnO VA KHA N A N G U N G DUNG CUA CHUNG Ma so: QT - 08 - 16 Chu tri de tai: PGS TS Ta Dinh Canh Can bo tham gia: CN Nguyin Viet Tuyen Muc tieu de tai: Trong cac hop chat ban dan, ZnO la chat ban dan c6 rong vomg cam Ion (-'3,3eV a nhiet phong), ben vung va nhiet nong chay cac, gia re ZnO thiromg dugc dung lam vat lieu cho cac Hnh kien quang dien tir ZnO c6 hieu suat lucmg tu phat quang c6 the dat tai gan 100%, ma trien vong viec che tao laser ZnO nhiet phong Mang mong ZnO CO dan dien va truyen qua quang hoc cao mien anh sang nhin thay dugc umg dung lam dien cue suot cho pin mat trai chat lirgmg cao va gia Cac mang ZnO dan dien suot dirge su dung cac man T t ' / hinh tinh the long, cac cOra so dien tir, cac thiet bj quang hoc uon dugc, cac gu^ong phan xa nhiet de phii va kho phu, tham chi hot ZnO c6 ung dung che tao kem chong nang Dae biet, nhiJng nam gan day, cac nha khoa hoc tren the gicri dang tap trung nghien curu vat lieu ZnO cau true nano vai nhieu hy vgng viec che tao mot the he linh kien mai c6 nhieu tinh chat UTJ viet so vai cac mau khoi Noi dung nghien ciifu: De thuc hien dirge muc tieu neu d tren, d^ tai da giai quyet dugc eac vSih de sau: + Che tao mang ZnO c6 chat liigng cao bang phuofng phap phun xa r.f magnetron tren thiet bj Univex - 450 cua hang Leybold - Lam chu dugc thiet bi Univex - 450 cua hang Leybold - Che tao bia ZnO va ZnO pha tap tiT bot ZnO va b6t In203 cua hang Merck bang phuofng phap gdm tmyen thong tren cac thiet bi cua du an OPEC + Che tao mang In+Al bang phuong phap boc bay nhi^t chan khong Cac ket qua dat dirac: + Dua cac thiet bi che tao mang mong bang phun xa catdt Univex-450 va boc bay nhiet chan khong Univex-300 vao boat d6ng c6 hieu qua + Che tao cong cac loai bia ZnO va ZnO pha tap bang phuofng phap gom truy6n thong -h Tim dugc che cong nghe de che tao mang ZnO va mang ZnO pha tap In tren de p-Si va de thuy tinh bang phucDmg phap phun xa r.f magnetron tren thiet bi Univex-450 + Che tao mang quang tra ZnO nhay a vung UV + Che tao cong pin mat trai n-ZnO: In-p-Si de lam cam bien nhay quang I I f f + iJng dung lap chuyen tiep p-n lam cam bien dong ma tu dgng den duong + Cong tac nghien curu: 1/ Preparation ofn-ZnOAn/p-Si heteroj unction by r.f magnetron sputtering Nguyen Viet Tuyen, Ta Dinh Canh, Pham Van Ben, Bach Van Sy, Nguyen Xuan Nghia, Tran Thi Quynh Hoa and Nguyen Ngoc Long Proceedings of the eleventh Vietnam-German seminar on Physics and Egineering, Nha trang 2008 (In the press) 2/ Photoconductive UV detectors based on ZnOfdms prepared by RF magnetron sputtering method, Nguyen Viet Tuyen, Ta Dinh Canh and Nguyen Ngoc Long Comm In Physics, 2008 (in the press) -h Cong tac dao tao : * Da hudng dan khoa luan tot nghiep 1/ Nguyen Si Hieu, ''Che tao va khao sat mang ZnO d6' thuy tinh bang hoc bay nhiet kem axetat chan khong" Ha Ngi - 6/200L 2/ Nguyen Hong Viet, "Che tao va khao sat mang ZnO pha tap Al tren de thuy tinh bang phuong phap phiin xa R F magnetron", Ha Ngi- 6/2002 * Da hudng dan luan van cao hoc: r 1/ Bach Van Sy, ''Che tao va khao sat mang ZnO, ZnO pha tap lam sensa nhay quang vung UVva VIS''' - Ha Noi, 12/2008 * Dang hirdng dan nghien curu sinh hu6ng nghien curu Tinh hinh su dung kinh phi: Tong kinh phi thirc chi: 20.000.000 d6ng (mudi lam trieu dong chan), Trong cac khoan da chi: Thanh loan dich vu cong c6ng : 600.000 d (tien dien) Thue mu6n : 8.500.000 d Chi phi nghiep vu chuyen mon : 10.300.000 d Chi phi khac (QLCS): 600.000 d Da thSng qua churng tijr tai phong tai vii Xac nhan ciia ban chii nhiem Khoa (Ky va ghi ro ho ten) PGS.TS.Nguyen The Binh Xac nhan ciia Trucmg DHKHTN » M HI?U o l;^-: D A I I TRl/ONG Chii tri di tM (Ky va ghi ro ho ttn) PGS.TS.Ta Dinh Onh Brief of the Report The title of the project Fabrication, investigation the properties of n-p heterojuction based on ZnO thin films and their ability of applications The code number: QT - 08 - 16 Main responsible person: assoc prof Dr Ta Dinh Canh Main implementation numbers: Bachelor Nguyen Viet Tuyen The objects The n-ZnO:In/p-Si heterojunction solar cells were made by magnetron sputtering The wavelength dependent properties of the photoresponse for the heterojunction were investigated in detail by studying the effect of light illumination on current - voltage (I-V) characteristic, photocurrent spectra at room temperature From the photocurrent spectra, it was observed that the visible photons are absorbed in the p-Si layer and under reverse bias conditions, while ultraviolet (UV) photons are absorbed in the depleted n-ZnO:In under reverse bias conditions These resuhs indicated that ZnO:In films prepared by the r.f magnetron sputtering are good enough to be used in photoelectrical devices The content of research The p-type Si (100) wafers (7-25 Qcm) were used as substrates for the ZnO:In/Si heterojunction Si (100) wafers were cut into pieces of lilcm Prior to the deposition, the wafers were dipped into buffered oxide etchant (HF:H20 = 1:7) for minute to remove native oxide Then the samples were ultrasonically cleaned with boiling acetone, ethanol, and de-ionized water for 10 ZnO:In films were deposited with an r.f magnetron sputtering system using a ZnOiIn (2%) target with diameter of 7.5 cm and 0.5 cm thick The sputtering parameters were optimized at a substrate temperature of 150 ''C, r.f power of 250 W and sputtering Ar pressure of 5.8110'^ Torr After the ZnO:In film was deposited, for measuring the electrical properties, an hi ohmic contact (0.5 mm diameter) was made onto the ZnO:In films being used as a top electrode and an In-i-Al ohmic contact was made onto the p-Si substrate being used as a bottom electrode The resistivity of the ZnO:In film was measured with a four-point probe system The dark current-voltage (LV) measurements were done keeping the sample in the dark for several hours by using a Keithley multimeter (Model 2400) Results: 1/ Preparation ofn-ZnO:In/p-Si heterojunction by r.f magnetron sputtering Nguyen Viet Tuyen, Ta Dinh Canh, Pham Van Ben, Bach Van Sy, Nguyen Xuan Nghia, Tran Thi Quynh Hoa and Nguyen Ngoc Long Proceedings of the eleventh Vietnam-German seminar on Physics and Egineering, Nha trang 2008 (In the press) 2/ Photoconductive UV detectors based on ZnOfdms prepared by RF magnetron sputtering method Nguyen Viet Tuyen, Ta Dinh Canh and Nguyen Ngoc Long Comm In Physics, 2008 (in the press) 7.Conclusion * Obtaining the aims of the project * Training graduate students, master student MUC LVC Trang MQ DAU Chuang 1: TONG QUAN VE VAT LY BAN DAN 1.1 Co so phan loai vat lieu 1.2 Phan loai vat lieu ban dan 1.2.1 Ban dan thuan 1.2.2 Ban dan loai p 1.2.3 Ban din loai n 1.3 CSu true tinh thi ZnO 11 1.3.1 Cau true tinh the ZnO luc giac 11 1.3.2 cau true tinh thi ZnO don gian kidu NaCl 12 1.3.3 Cau true mang lap phuong gia kem (zine blend) 13 1.4 Cau tnic viing nang lugng cua ZnO 14 1.4.1 Cau tnic vung nang lugng cua ZnO dang luc giac 14 1.4.2 Cau true vung nang lugng cua ZnO dang gia kem 15 1.4.3 Cau tnic vung nang lugng cua ZnO dang lap phuong dan gian ki6u NaCl 16 1.5 Tinh chat dien ciia ZnO 17 1.5.1 Dich chuyen dien trucmg thap 17 1.5.2 Dich chuyen dien trucmg cao 18 1.5.3 Tinh chat dien cua ZnO pha tap 19 1.5.3.1 Tinh chat dien ciia ZnO pha tap loai n 19 1.5.3.2 Tinh chat dien cua ZnO pha tap loai p 20 1.6 Tinh chat quang cua vat lieu ban dan 23 1.6.1 Cac dac trung quang 23 1.6.2 Cac CO chi hdp thu anh sdng 24 1.7 Tinh chat quang cua ZnO 27 1.7.1 Cac exciton tu 27 1.7.2 Cac exciton lien ket 28 1.8 Cac tiep xiic ban din 30 1.8.1 Tilp xuc p-n dong thi 30 1.8.2 Tiep xuc p-n di the 31 1.8.3 Tiep xuc Ohmic 33 Chuang 2: CAC PHUONG PHAP THI/C NGHIEM 36 2.1 Cac ky thuat phun xa 36 2.1.1 Phiin xa nguon mot chieu 37 2.1.2 Phiin xa nguon xoay chieu 39 2.1.3 Phiin xa magnetron 40 2.2 Nghien curu cau tnic bang phuang phap nhilu xa tia X 41 2.3 Quan sat hinh thai be mat bang kinh hiln vi dien tu quet (SEM) 43 2.4 Do dien tra suat 43 Chuang 3: KET QUA,BIEN LUAN, VA iTNG DUNG 45 3.1 Che tao va khao sat lap chuyen tiep n-ZnO:In/p-Si 45 3.1.1 Khao sat cau tnic 45 3.1.2 Khao sat tinh chat quang 46 3.1.3 Khao sat tinh chSt dien 48 3.2 Sur dung lop chuyin tiep n-ZnO:In/p-Si lam thiet bi dong ngat tu dong he thong chieu sang den duong 50 3.2.1 So ddkhdi 50 3.2.2 So d6 chi ti8t 51 KET LUAN 53 TAI LIEU THAM KHAO 54 MOfDAU Trong cac hgp chat ban din, ZnO la chit ban din c6 dg rgng viing cam Ian (-3,3eV d nhiet phong), ben vvhig va nhiet nong chay cao, gia re ZnO thuang dugc diing lam vat lieu cho cac linh kien quang dien tu ZnO c6 hieu suat lugng ^ y t ' tu phat quang c6 the dat tai gan 100%, ma trien vgng viec che tao laser ZnO nhiet phong Mang mong ZnO c6 dan dien va truyen qua quang hgc cao mien anh sang nhin thay dugc ung dung lam dien cue suot cho pin mat trai chat lugng cao va gia Cac mang ZnO dan dien suot dugc su dung cac man hinh tinh the long, cac cua so dien tu, cac thiet hi quang hgc uon dugc, cac guang phan xa nhiet de phii va kho phu, tham chi bgt ZnO c6 ung dung che f r \ ' tao kem chong nang Dac biet, nhumg nam gan day, cac nha khoa hgc tren the giai dang tap trung nghien curu vat lieu ZnO cau tnic nano vai nhieu hy vgng viec che tao mot the he linh kien mai c6 nhieu tinh chat uu viet so vai cac mau khoi Communications in Physics, Vol ??, No ? (2005J, pp 1-?? P H O T O C O N D U C T I V E U V D E T E C T O R S B A S E D O N ZnO FILMS P R E P A R E D B Y R.F M A G N E T R O N S P U T T E R I N G M E T H O D NGUYEN V I E T TUYEN.TA DINH CANH AND NGUYEN NGOC LONG Department of Physics, Hanoi University of Science, VNU-Hanoi Abstract Highly c-aocis oriented zinc oxide (ZnO) thin films were deposited on glass substrates by radio frequency (r.f) sputtering The photoconductor UV detector based on ZnO films, having a metal-semiconductor-metal (MSM) structure with interdigitation configuration, were fabricated by using aluminium (Al) as a contact metal The characteristics of dark and photocurrent of the ultraviolet (UV) detector and the UV photo-response of the detector were investigated The linear current-voltage (I-V) characteristics under both forward and reverse bias exhibit ohmic metal-semiconductor contracts Under illumination by monochromatic light at a wavelength of 365 nm, the photo-generated current was measured to be 0.56 (xA at a bias of V The photo-response decay in these devices is stow Keywords: R.F magnetron sputtering, ZnO thin film, Photoconductive UV detector, Ohmic contact, Photo-responsivity I I N T R O D U C T I O N ZnO is a wide and direct band gap (3.3 eV) semiconductor material with hexagonal wurtzite structure and has potential applications for surface acoustic wave devices (SAW), gas sensors, transparent conducting layers, light emitting diodes (LEDs), ultraviolet (UV) lasers and especially the UV detector [1,2] The reports of ZnO UV detector mainly focus on metal/semiconductor/metal (MSM) structure which contains ohmic contact based photoconductive type [3,5] and schottky-barrier-based photovoltage type [4,6,7] The photoconductive detector is easy to achieve higher gain and photoresponsitivity, but the photoresponse time is usually longer than other types because of the persistent photoconductivity In this report, we describe the photoconductivity in the UV region of ZnO thin films grown by a sputtering method and show that the ZnO thin films are advantageous and promising materials for use in ultraviolet sensor II E X P E R I M E N T ZnO thin films were prepared by a radio frequency (r.f.) sputtering device which has a bcise pressure of 5.8 x 10~^ Torr Glass substrates with the size of 20 x 20 cmwere placed on the sample holder which is parallel to the 75 mm ZnO target Before sputteriug, the glasses were ultra-sonically cleaned sequentially in distilled water, acetone, alcohol, and distilled water again After minutes of sputtering in argon (Ar) plasma, with r.f i)ower of 2(^0 W at deposition temperature of 150 "C a ZuO thin fihi v.'as ilt'[>ijsitcd on t h e glass (the thickness of the ZnO thin film is about (.1.6 /uu) Almniiiium was w^^i-d as NGUYEN VIET TUYEN, TA DINH CANH, NGUYEN NGOC LONG a contact metal because of its electron negativity A 200 nm thick Al film electrode with interdigitation (IDT) configuration was patterned on the sputtered ZnO surface with a shadow mark by thermal evaporation at 250 ^C T h e crystal structure and growth direction were investigated by using a X-ra>' difFractometer (D5005, Bruker, Germany), and the surface morphology was studied by using a scanning electron microscope (JSM 5410 LV, Jeol, Japan) and an atomic force microscope ( A F M ) T h e optical properties in the visible region were studied by employing an U V / V I S spectroscope (UV 2450 P C , Shimadzu, Japan) and the photoluminescence (PL) spectra were measured at room temperature by a spectrofluorometer (FL 3-22, Jobin YvonSpex, USA) III R E S U L T S A N D D I S C U S S I O N T h e ZnO film, prepared with a ZnO target, exhibited columnar grain growth with a strong c- axis orientation perpendicular to the substrate surface Fig shows a typical X-ray diffraction p a t t e r n for the ZnO films 0.8