Zn1-xMgxO薄膜p型导电和光学性能

采用超声喷雾热分解(Ultrasonic Spray Pyrolysis,USP)方法,以醋酸锌、醋酸镁、醋酸铵、氯化铝的混合水溶液为前驱溶液,在单晶Si(100)衬底上制备了ZnO,Zn_0.81Mg_0.19O,N-Al共掺杂ZnO和N-Al共掺杂Zn_0.81Mg_0.19O薄膜。以X射线衍射(XRD)、场发射-扫描电镜(FE-SEM)、霍尔效应(Hall-effect)、光致发光(Photoluminescence,PL)谱等手段研究了薄膜的晶体结构、表面形貌、电学性能、光学性能和带隙变化。电学测试结果表明,未掺杂ZnO及Zn_0.81Mg_0.19O薄膜为n型导电;而N-Al共掺杂ZnO和N-Al共掺杂Zn_0.81Mg_0.19O薄膜呈p型导电。Zn_0.81Mg_0.19O和N-Al共掺杂Zn_0.81Mg_0.19O(p型)薄膜在维持ZnO纤锌矿结构的前提下,光学带隙随Mg掺杂量增加而增大。初步结果显示,优化工艺参数下通过Mg掺杂制备光学带隙可调的p型Zn_0.81Mg_0.19O薄膜,对于试制Zn_1-xMg_xO基同质p-n结、短波长(紫外、深紫外)器件等方面有重要意义。

p-type Conduction and Optical Properties of Zn1-xMgxO Thin Films Grown by Ultrasonic Spray Pyrolysis

ZnO,N-Al codoped ZnO,Zn_(0.81)Mg_(0.19)O,N-Al codoped Zn_(0.81)Mg_(0.19)O thin films have been deposited on Si(100) substrates as the precursory sources of Zn(CH_3COO)_2,Mg(CH_3COO)_2,NH_4CH_3COO and AlCl_3 aqueous solutions using ultrasonic spray pyrolysis(USP) method.The crystalline structure,morphology images,electrical,optical properties and band gap of the films are characterized by X-ray diffraction(XRD),field emission-scan electron microscopic image(FE-SEM),Hall-effect measurement and photoluminescence(PL). The XRD patterns reveal that all the films are composed of wurtzite-type ZnO phase.No peak originating from other compounds is detected except those of ZnO.From the SEM images,we can see that all the films present good morphologic uniformity,smooth dense surface,no visible pores and defects over the film.Apart from that,there are some grain morphology differences between Zn_(0.81)Mg_(0.19)O and p-Zn_(0.81)Mg_(0.19)O films,perhaps due to the different nucleation modes resulted from different dopants.Hall-effect measurement results indicate that ZnO and Zn_(0.81)Mg_(0.19)O are n-type,while N-Al codoped ZnO and N-Al codoped(Zn_(0.81)Mg_(0.19)O) exhibit p-type conductivity.From the PL peaks of ZnO and Zn_(0.81)Mg_(0.19)O,it can be seen that Zn_(0.81)Mg_(0.19)O is tuned into shorten wavelength than pure ZnO.Furthermore,the photoluminescence peak of p-Zn_(0.81)Mg_(0.19)O film (exhibits) also blue-shift behavior from 378 to 356 nm compared with p-ZnO film.Accordingly,the band gap of p-Zn_(0.81)Mg_(0.19)O film increases with the Mg content increases compared with p-ZnO film.In addition,The growth rate dependence of electrical and PL properties in p-Zn_(1-x)Mg_xO films are also(discussed.) Only upon moderate growth rate,the p-Zn_(0.81)Mg_(0.19)O film exhibits both good electrical and(excellent) PL(properties.) In conclusion,optimal growth conditions confirm that Zn_(0.81)Mg_(0.19)O films,both wide band gap and p-type conductivity,are successfully fabricated by codoping of N and Al using USP method,which are of(significant) importance for practical(applications) of Zn_(1-x)Mg_xO p-n homojunctions and Zn_(1-x)Mg_xO-based UV optoelectrical devices.