镓铝砷双异质结红光二极管中红外辐射起因的研究

本文研究了镓铝砷双异质结红光二极管发射光谱中的红外谱带随工作电流及温度的变化规律,并看到器件的发光效率与红外带的强度有明显的联系.通过红外带峰值位置,半值宽度、峰值位置随温度的移动及发光区深能级的测定,认为该谱带来源于衬底.由于有源区厚度的不均匀及限制作用不充分,使注入到有源区中的一部分电子能穿过限制层进入P型GaAs衬底,从而产生红外谱带.指出改善有源区厚度均匀性,增大限制层的势垒高度是降低红外辐射,提高器件发光效率的有效途径.

STUDY OF THE ORIGIN OF INFRARED EMISSION IN GaAlAs DH RED LED's

Ga1-xAlxAs red DH LED shown in Fig.1 has been prepared.Compared with SH device its luminous flux has remarkably increased and reached 22mLm at 20mA.There is a stronger infrared peak at about 890 nm in EL spectrum besides a red main peak. It is found that the relative intensity of the infrared band to the red one is related to the luminous efficiency of devices.The stronger the infrared emission is, the poorer the efficiency(see Table 1). This implies that a part of injection energy is expended in generating the infrared emission which does not contribute to luminous flux. Therefore, to find out the origin of the infrared emission and then to eliminate it will raise the luminous efficiency of devices in the furture.