High performance, high bandgap, lattice-mismatched, GaInP solar cells

Patent metadata

Field	Value
Publication number	US-9484480-B2
Application number	US-201414313720-A
Country	US
Kind code	B2
Filing date	Jun 24, 2014
Priority date	Dec 30, 2004
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

High performance, high bandgap, lattice-mismatched, photovoltaic cells ( 10 ), both transparent and non-transparent to sub-bandgap light, are provided as devices for use alone or in combination with other cells in split spectrum apparatus or other applications.

First claim

The invention claimed is:

1. A photovoltaic converter comprising:
a photovoltaic cell comprising GaInP having a bandgap greater than about 1.9 eV, wherein the photovoltaic cell has a junction and is lattice-mismatched to a parent substrate; and
a graded layer positioned between the parent substrate and the photovoltaic cell, wherein:
the parent substrate comprises GaAs,
the graded layer has a lattice constant that changes from a first lattice constant in a first portion closest to the parent substrate to a second lattice constant in a second portion closest to the photovoltaic cell, such that the second lattice constant matches a relaxed lattice constant of the photovoltaic cell,
the photovoltaic cell includes an emitter on a front side of the junction and a base on a back side of the junction, and
the photovoltaic converter further comprises: (i) a double heterostructure comprising a back surface confinement layer on the base and a passivation/window layer on the emitter; (ii) a front contact layer comprising doped GaAsP between a metal grid and the passivation/window layer; (iii) an anti-reflection coating on the passivation/window layer between contacts of the front contact layer; and (iv) a back contact layer comprising doped GaAsP on the back surface confinement layer.

2. The photovoltaic converter of claim 1 , further comprising a transparent handle mounted adjacent to the front contact layer.

3. A photovoltaic converter comprising:
a photovoltaic cell comprising GaInP having a bandgap greater than about 1.9 eV, wherein the photovoltaic cell has a junction and is lattice-mismatched to a GaAs parent substrate; and
a graded layer positioned between the parent substrate and the photovoltaic cell, wherein:
the graded layer comprises GaAs 1-x P x, and “x” increases in discrete incremental steps from a first value in a first portion closest to the parent substrate to a second value in a second portion closest to the photovoltaic cell until the proportions of As and P are such that the GaAs 1-x P x in the second portion has a lattice constant that matches a relaxed lattice constant of the photovoltaic cell,
the graded layer comprises 6 to 10 steps of GaAs 1-x P x ,
each step is between about 1.0 μm and about 2.2 μm thick,
the P content increases and the As content correspondingly decreases from the first portion to the second portion by about 4 percent to about 6 percent per step, and
a last step in the second portion comprises between about 30 percent and 44 about percent P.

4. The photovoltaic converter of claim 3 , wherein:
the photovoltaic cell includes a base on a back side of the junction and an emitter on a front side of the junction, and
the photovoltaic converter further comprises: (i) a double heterostructure comprising a back surface confinement layer between the graded layer and the base, and a passivation/window layer on the emitter; (ii) a contact layer comprising doped GaAsP between a metal grid and the passivation/window layer; (iii) an anti-reflection coating on the passivation/window layer between contacts of the contact layer; and (iv) an electrically conductive back contact on a back side of the parent substrate.

5. A photovoltaic converter comprising:
a photovoltaic cell comprising GaInP having a bandgap greater than about 1.9 eV, wherein the photovoltaic cell has a junction and is lattice-mismatched to a GaAs parent substrate; and
a graded layer positioned between the parent substrate and the photovoltaic cell, wherein:
the graded layer comprises GaAs 1-x P x , and “x” increases from a first value in a first portion closest to the parent substrate to a second value in a second portion closest to the photovoltaic cell until the proportions of As and P are such that the GaAs 1-x P x in the second portion has a lattice constant that matches a relaxed lattice constant of the photovoltaic cell,
the photovoltaic cell includes an emitter on a front side of the junction and a base on a back side of the junction, and
the photovoltaic converter further comprises: (i) a double heterostructure comprising a back surface confinement layer on the base and a passivation/window layer on the emitter; (ii) a front contact layer comprising doped GaAsP between a metal grid and the passivation/window layer; (iii) an anti-reflection coating on the passivation/window layer between contacts of the front contact layer; and (iv) a back contact layer comprising doped GaAsP on the back surface confinement layer.

6. The photovoltaic converter of claim 5 , further comprising a transparent handle mounted adjacent to the front contact layer.

Assignees

• Alliance Sustainable Energy

Inventors

• Wanlass Mark W
• Carapella Jeffrey J
• Steiner Myles A

Classifications

• H01L31/02168

  Electricity · mapped topic

• H01L31/065 Primary

  Electricity · mapped topic

• H01L31/06875

  Electricity · mapped topic

• H01L31/1844

  Electricity · mapped topic

• H01L31/068

  Electricity · mapped topic