Responsivity properties of ZnTe/GaAs heterostructures formed with pulsed-laser deposition

In situcharacterization of ZnTe epilayer irradiation via time-resolved and power-density-dependent Raman spectroscopy

“…In recent years the compound ZnTe experienced strong interest in the field of semiconductor physics and optoelectronics. Since its band gap energy is in the region of 2.26 eV [1], it is an appropriate material for use in green-emitting optical devices or in elements absorbing at this wavelength region like solar cells [2,3]. Additionally this compound exhibits the capability of easy p-type doping for the fabrication of optical devices.…”

Doping of GaAs by laser ablated ZnTe

“…This sample was chosen because it revealed a pronounced DAP feature in DC photocurrent spectra measured without externally applied bias. 10 Close to the DAP transition around 1.35 eV the spectrum reveals a feature in the transmittance. In order to check whether the energy position of the transition can be pinpointed we applied the common praxis by plotting (ahm) 2 vs. hm, where hm is the photon energy and a is the absorption coefficient.…”

“…The narrow peak below the band gap points clearly to a distinct extrinsic transition in the crystalline GaAs substrate such a donoracceptor pair (DAP) transition. 9,10 The band gap shrinking mechanism due to many body effects is ruled out to be the origin of the observed narrow responsivity peak since it causes a shift of the entire absorption edge rather than distinct narrow peaks below the fundamental transition. 13 The DAP transition energy is expressed by 4,5…”

“…5,7,8 In the past doping was achieved by using doped targets for the ablation, whereas, we discovered that it is possible to form donor and acceptor states in GaAs by depositing laser ablated ZnTe (@1064 nm, 6 ns, 10 Hz) onto a GaAs substrate. 9, 10 We referred this phenomenon to photonic doping, and in this letter we show our latest results regarding the subject.…”

“…[9][10][11] Pure ZnTe (four 9s) was ablated for 1 h in a vacuum (10 À4 -10 À5 Pa) with ultraviolet, green and infrared irradiation at 355 nm, 532 nm, and 1064 nm with a fluence of 0.78 6 0.07 J/cm 2 , 0.96 6 0.08 J/cm 2 , and 0.91 6 0.09 J/cm 2 employing a Nd:YAG laser (6 ns, 10 Hz). The ZnTe films with a thickness of 1.3-2.5 lm have been deposited by low-temperature PLD, i.e., without heating the substrate, which was an industrial 2 in.…”