Simple theoretical analysis of the photoemission from quantum confined effective mass superlattices of optoelectronic materials

Debashis De,S M Adhikari,Sitangshu Bhattacharya,P K Bose,K P Ghatak,A Kumar

doi:10.3762/bjnano.2.40

Abstract

The photoemission from quantum wires and dots of effective mass superlattices of optoelectronic materials was investigated on the basis of newly formulated electron energy spectra, in the presence of external light waves, which controls the transport properties of ultra-small electronic devices under intense radiation. The effect of magnetic quantization on the photoemission from the aforementioned superlattices, together with quantum well superlattices under magnetic quantization, has also been investigated in this regard. It appears, taking HgTe/Hg1−xCdxTe and InxGa1−xAs/InP effective mass superlattices, that the photoemission from these quantized structures is enhanced with increasing photon energy in quantized steps and shows oscillatory dependences with the increasing carrier concentration. In addition, the photoemission decreases with increasing light intensity and wavelength as well as with increasing thickness exhibiting oscillatory spikes. The strong dependence of the photoemission on the light intensity reflects the direct signature of light waves on the carrier energy spectra. The content of this paper finds six different applications in the fields of low dimensional systems in general.

Highlights

With the advent of modern fabrication techniques [1], semiconductors with superlattice structures (SLs) [2], in which alternate layers of two different degenerate materials set up a periodic potential with a periodicity many times the crystal dimensions [3], resulting in energy mini-bands, have been experimentally realized [4]
The III–V SLs are being extensively used in the realization of high speed optoelectronic devices [10]
The IV–VI SLs shows new physical properties in comparison with the III–V SL owing to the peculiar band structure of the constituent materials [14]

Summary

Introduction

With the advent of modern fabrication techniques [1], semiconductors with superlattice structures (SLs) [2], in which alternate layers of two different degenerate materials set up a periodic potential with a periodicity many times the crystal dimensions [3], resulting in energy mini-bands, have been experimentally realized [4]. The II–VI [11], IV–VI [12] and HgTe/CdTe [13] SLs have been experimentally realized. HgTe/CdTe SLs find applications for long wavelength infrared detectors and other electro-optical applications [15]. These features arise from the direct band gap compound CdTe whose conduction electrons obey the three band model of Kane and gap-less material HgTe [16]. In this context, it may be noted that in the effective mass SLs, the subbands of the electrons exist in real space [17]

Objectives

Methods

Results