Electrochemical capacitance-voltage profiling of nonuniformly doped GaAs heterostructures with SQWs and MQWs for LED applications

George Yakovlev,Anna Solomnikova,Oleg Derevianko,Vasily Zubkov

doi:10.3906/fiz-1803-23

Abstract

Light-emitting heterostructures with single and multiple GaAs/InGaAs quantum wells have been investigated by means of electrochemical capacitance-voltage (ECV) profiling. Capacitance-voltage characteristics were measured; concentration profiles of free charge carriers over the heterostructure depth as well as the intensity of quantum well filling by charge carriers were obtained. In heterostructures with a single quantum well (QW), we considered limitations of capacitance techniques for undoped QW profiling, which are situated near the metallurgic border of the p-n junction. We made a detailed consideration of phenomena related to Debye smearing and we developed and analyzed the dependence of the space charge region width on the doping. Special attention was paid to investigation of "the blind" area. This was inspired by the practical problem from capacitance spectroscopy of semiconductors, when the researcher poses the task of obtaining a free charge carrier depth distribution profile as deep as possible in the space charge region, i.e. where the intensity of the electric field is maximum. Generally, the active QW of a LED heterostructure is placed deep in the space charge region, so reaching these regions is extremely important for practical problems. We present an evolution of capacitance-voltage characteristics during ECV profiling of nonuniformly doped p-n-heterostructures. For a heterostructure with multiple quantum wells, we registered a response from 6 QWs.

Highlights

Semiconductor heterostructures with single quantum wells (SQWs) and multiple quantum wells (MQWs) are successfully used for nano- and optoelectronics devices such as light-emitting diodes, lasers, and photodetectors [1,2,3,4,5,6]
The apparent advantage of the electrochemical capacitance-voltage (ECV) technique is the possibility of profiling in the etching mode; even in this case we do not see a response from the QW at the concentration profile
Electrochemical capacitance-voltage profiling was used to investigate a set of IR light-emitting heterostructures with SQWs and MQWs based on GaAs/InGaAs

Summary

Introduction

Semiconductor heterostructures with single quantum wells (SQWs) and multiple quantum wells (MQWs) are successfully used for nano- and optoelectronics devices such as light-emitting diodes, lasers, and photodetectors [1,2,3,4,5,6]. The electrochemical capacitance-voltage (ECV) profiling technique allows one to obtain information about both impurity distribution and FCC concentration [14].

Results

Conclusion