GaN基450nm波长LD在阈值处的反常电学特性  

Abnormal electrical propoerties of GaN-LDs with 450 nm wavelength in lasing threshold region

作　　者：杨秀芳[1] 赵昆[1] 李倩倩[1] 杜江涛[1] 王存达[1] 冯列峰[1] 

机构地区：[1]天津大学理学院天津市低维功能材料物理与制备技术重点实验室,天津300072

出　　处：《光电子．激光》2015年第6期1036-1040,共5页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(11204209;60876035);天津市自然科学基金重点(13JCZDJC32800);海南省自然科学基金(613173);天津大学自主创新(2014XRG-0102)资助项目

摘　　要：精确表征了GaN基450nm波长LD的电学特性,表观测量的电学参量在阈值附近都出现了明显的突变。器件的(IdV/dI-I)曲线在阈值处突然上跳。与此对应,其他电学参量在阈值处的突变也与以往观察到的窄带隙780nm波长LD在阈值处的突变完全反向。表观特性的反常必定造成反常的结特性,利用ac-IV方法精确表征了器件的结特性,在阈值区各结电学参量的突变趋势与以往报道的窄带隙780nm波长LD也完全相反。光学实验表明,在阈值区内(约3mA)光功率增加近1个量级。光特性的突然增加必定与电学特性的突变存在必然联系。所有这些反常的电学特性是传统的激光器理论难以解释的,将促使LD理论的进一步发展。The electrical properties of GaN-based laser diode （LD） with 450 nm wavelength were measured using the electrical derivative technology and a precision impedance analyzer. The sudden changes of the apparent characteristics including （IdV/dI） I, Cp-I and Gp-I curves in the lasing threshold region were observed. However,in this region,its （IdV/dI） /curve displays a sudden jump rather than a drop reported in previous references. Correspondingly, the change trends of Cp-I and Gp-I curves in the threshold region are also obviously opposite to those in the narrow band-gap LDs. The same abnormal results between the wide-band CaN based LD and the narrow band-gap LDs can be observed in the junction parameters extracted accurately by our ac-IV method,namely,all junction parameter curves display sudden changes in the threshold region but their change trends are also opposite to those in the narrow band-gap LDs reported in our previous papers. In the threshold region,the optical power increases by an order of magnitude,which could have an intimated relationship with the sudden increase of the junction voltage. All these abnormal electrical properties in wide band-gap LDs conflict with the current lasing theory,so it will promote further improvement of the laser theory.

关 键 词：GAN 激光阈值 LD 不连续电学特性 

分 类 号：TN304.07[电子电信—物理电子学]